Bio

Honors & Awards


  • Charles E. Smith Memorial Award, Coccidioidomycosis Study Group (2006)
  • Lucille Georg Medal, International Society for Human and Animal Mycology (2006)
  • Outstanding Achievement in Medicine Award, Santa Clara County Medical Association (2003)
  • Rhoda Benham Medal, Medical Mycology Society of the Americas (1999)

Research & Scholarship

Current Research and Scholarly Interests


Dr. Stevens' group studies the biology, immunology, epidemiology and therapy of fungal infections. They are using molecular fingerprinting systems applied to the genomes of Candida species to develop tools to allow typing and differentiation of clinical isolates and for epidemiological and taxonomic purposes. Fungal signatures are sought in development of rapid and sensitive diagnostic techniques. Animal models are developed and used to study differences in virulence in fungal strains, their biochemical characterization and interaction with host defenses, particularly the role of therapy with recombinant cytokines and other immunomodulators, and preclinical studies of diagnosis. The infections most intensively investigated, with respect to pathogenesis or therapy, are pulmonary and disseminated aspergillosis, coccidioidal meningitis and pulmonary blastomycosis. The laboratory is working on development of vaccines against Coccidioides and Aspergillus. The chemotherapy of fungal infection is also under study including the evaluation of agents in vitro, and for their efficacy, pharmacology, and toxicology in animal models and in human disease. The laboratory is, in addition, a clinical reference laboratory for fungal and actinomycete susceptibility testing, and body fluid antifungal drug concentration determinations, for hospitals in the area. In collaborations with Latin America, the researchers are involved in the study of paracoccidioidomycosis. Mammalian estradiol influence on Paracoccidioides pathogenesis is being investigated by focusing on the block of morphogenetic transformation and the role of the fungal estradiol-binding protein. Paracoccidioides gene expression during morphogenesis, and the events in hormone-mediated block, are under study with DNA microarray technology.

Teaching

2013-14 Courses


Publications

Journal Articles


  • Mycologic catastrophe. Antimicrobial agents and chemotherapy Stevens, D. A. 2013; 57 (6): 2904-?

    View details for DOI 10.1128/AAC.00316-13

    View details for PubMedID 23674752

  • Halomonas johnsoniae: review of a medically underappreciated genus of growing human importance. The American journal of the medical sciences Stevens, D. A., Kim, K. K., Johnson, N., Lee, J., Hamilton, J. R. 2013; 345 (5): 335-338

    Abstract

    The growing genus Halomonas includes bacteria favoring or tolerating high-saline/halide and high-pH environments. Infections are rarely reported. A patient developed Halomonas johnsoniae (previously reported only as dialysis unit environmental contaminants) bacteremia. The medical community is alerted to the pathogenic potential of the genus, particularly in a dialysis setting.

    View details for DOI 10.1097/MAJ.0b013e31825600de

    View details for PubMedID 22814360

  • Experimental Evidence That Granulocyte Transfusions Are Efficacious in Treatment of Neutropenic Hosts with Pulmonary Aspergillosis ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Martinez, M., Chen, V., Tong, A., Hamilton, K., Clemons, K. V., Stevens, D. A. 2013; 57 (4): 1882-1887

    Abstract

    Although polymorphonuclear leukocytes (PMNs) are powerfully anti-Aspergillus, transfusion therapy remains controversial, with conflicting results, and experimental support has been lacking. We devised a pulmonary infection model in neutropenic BALB/c mice, used an antibacterial regimen to prevent confounding sepsis, and optimized PMN induction, purifications, and dose. Mice were given 150 mg/kg cyclophosphamide every 4 days and a gentamicin-vancomycin-clindamycin-imipenem regimen daily beginning 4 days before intranasal challenge with 5 × 10(5) Aspergillus conidia. This regimen produced leukopenia (~10% of normal white blood cell [WBC] count; ? 10% PMNs) for 10 days, without bacterial superinfection. PMN donors given 100 ?g/kg recombinant murine granulocyte colony-stimulating factor (G-CSF) for 10 days yielded 11 × 10(7) to 13.6 × 10(7) WBC/ml (81 to 87% PMNs). Infected mice were given PMN transfusions intravenously. In 2 experiments with up to 70% mortality of neutropenic controls, transfusion of 10(7) PMNs 1 and 4 days after challenge had negligible effects on peripheral WBC counts but improved survival (P = 0.007, 0.02), decreased lung CFU (P = 0.03, 0.005), and cleared infection in 28 to 50% of survivors. Transfusion of 5 × 10(6) PMNs showed partial protection. Transfusions given every other day did not improve protection. Our present results provide an experimental basis for enthusiasm for PMN transfusions in the therapy of aspergillosis in humans.

    View details for DOI 10.1128/AAC.02533-12

    View details for Web of Science ID 000316119100044

    View details for PubMedID 23380731

  • Reflections on the Approach to Treatment of a Mycologic Disaster ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Stevens, D. A. 2013; 57 (4): 1567-1572

    View details for DOI 10.1128/AAC.02242-12

    View details for Web of Science ID 000316119100001

    View details for PubMedID 23384533

  • Phylogenetic Analysis Reveals a Cryptic Species Blastomyces gilchristii, sp nov within the Human Pathogenic Fungus Blastomyces dermatitidis PLOS ONE Brown, E. M., McTaggart, L. R., Zhang, S. X., Low, D. E., Stevens, D. A., Richardson, S. E. 2013; 8 (3)

    Abstract

    Analysis of the population genetic structure of microbial species is of fundamental importance to many scientific disciplines because it can identify cryptic species, reveal reproductive mode, and elucidate processes that contribute to pathogen evolution. Here, we examined the population genetic structure and geographic differentiation of the sexual, dimorphic fungus Blastomyces dermatitidis, the causative agent of blastomycosis.Criteria for Genealogical Concordance Phylogenetic Species Recognition (GCPSR) applied to seven nuclear loci (arf6, chs2, drk1, fads, pyrF, tub1, and its-2) from 78 clinical and environmental isolates identified two previously unrecognized phylogenetic species. Four of seven single gene phylogenies examined (chs2, drk1, pyrF, and its-2) supported the separation of Phylogenetic Species 1 (PS1) and Phylogenetic Species 2 (PS2) which were also well differentiated in the concatenated chs2-drk1-fads-pyrF-tub1-arf6-its2 genealogy with all isolates falling into one of two evolutionarily independent lineages. Phylogenetic species were genetically distinct with interspecific divergence 4-fold greater than intraspecific divergence and a high Fst value (0.772, P<0.001) indicative of restricted gene flow between PS1 and PS2. Whereas panmixia expected of a single freely recombining population was not observed, recombination was detected when PS1 and PS2 were assessed separately, suggesting reproductive isolation. Random mating among PS1 isolates, which were distributed across North America, was only detected after partitioning isolates into six geographic regions. The PS2 population, found predominantly in the hyper-endemic regions of northwestern Ontario, Wisconsin, and Minnesota, contained a substantial clonal component with random mating detected only among unique genotypes in the population.These analyses provide evidence for a genetically divergent clade within Blastomyces dermatitidis, which we use to describe a novel species, Blastomyces gilchristii sp. nov. In addition, we discuss the value of population genetic and phylogenetic analyses as a foundation for disease surveillance, understanding pathogen evolution, and discerning phenotypic differences between phylogenetic species.

    View details for DOI 10.1371/journal.pone.0059237

    View details for Web of Science ID 000316549400044

    View details for PubMedID 23533607

  • Advances in systemic antifungal therapy CLINICS IN DERMATOLOGY Stevens, D. A. 2012; 30 (6): 657-661

    Abstract

    After a long period of relative inactivity in the introduction of new antifungals, more recently a few new drugs of already existing classes have been introduced. These represent small or large advantages and differences compared with existing available alternative therapy for deep and systemic mycoses. The 3 newest drugs include posaconazole, micafungin, and anidulafungin, whose pharmacology, toxicology, and indications are presented.

    View details for DOI 10.1016/j.clindermatol.2011.09.018

    View details for Web of Science ID 000310657400011

    View details for PubMedID 23068153

  • Vaccination with mannan protects mice against systemic aspergillosis MEDICAL MYCOLOGY Liu, M., Machova, E., Nescakova, Z., Medovarska, I., Clemons, K. V., Martinez, M., Chen, V., Bystricky, S., Stevens, D. A. 2012; 50 (8): 818-828

    Abstract

    Invasive aspergillosis is a major cause of mortality in immunocompromised patients and therapeutic options are often limited, thus a vaccine would be desirable. We presently studied acid-stable cell-wall mannan (?-1, 6-linked backbone highly branched with ?-1, 2; ?-1, 3; and ?-1, 2-linked manno-oligomers) derived from C. albicans, with or without conjugation to bovine serum albumin (BSA), as a vaccine against systemic aspergillosis. Mice were vaccinated subcutaneously with mannan or mannan-BSA conjugate weekly 3 times, ending 2 weeks prior to infection with A. fumigatus conidia. Results showed that the protection induced by mannan is dose-dependent; 12 mg unconjugated mannan alone or > 0.3 mg mannan-BSA consistently enhanced survival (P < 0.05). Fungal burdens in brains and kidneys were reduced after > 0.3 mg of mannan-BSA (all P < 0.05). Mannan-induced protection was improved about 40-fold by conjugation of BSA to mannan. Mannan-BSA (500 kDa) was more protective than 40 kDa mannan-BSA. Mannan is a candidate for a cross-protective conjugate fungal vaccine.

    View details for DOI 10.3109/13693786.2012.683539

    View details for Web of Science ID 000309936400005

    View details for PubMedID 22587733

  • Population Pharmacokinetics of Conventional and Intermittent Dosing of Liposomal Amphotericin B in Adults: a First Critical Step for Rational Design of Innovative Regimens ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Hope, W. W., Goodwin, J., Felton, T. W., Ellis, M., Stevens, D. A. 2012; 56 (10): 5303-5308

    Abstract

    There is increased interest in intermittent regimen of liposomal amphotericin B, which may facilitate use in ambulatory settings. Little is known, however, about the most appropriate dosage and schedule of administration. Plasma pharmacokinetic data were acquired from 30 patients receiving liposomal amphotericin B for empirical treatment of suspected invasive fungal infection. Two cohorts were studied. The first cohort received 3 mg of liposomal amphotericin B/kg of body weight/day; the second cohort received 10 mg of liposomal amphotericin B/kg at time zero, followed by 5 mg/kg at 48 and 120 h. The levels of liposomal amphotericin B were measured by high-pressure liquid chromatography (HPLC). The pharmacokinetics were estimated by using a population methodology. Monte Carlo simulations were performed. D-optimal design was used to identify maximally informative sampling times for both conventional and intermittent regimens for future studies. A three-compartment pharmacokinetic model best described the data. The pharmacokinetics for both conventional and intermittent dosing were linear. The estimates for the mean (standard deviation) for clearance and the volume of the central compartment were 1.60 (0.85) liter/h and 20.61 (15.27) liters, respectively. Monte Carlo simulations demonstrated considerable variability in drug exposure. Bayesian estimates for clearance and volume increased in a linear manner with weight, but only the former was statistically significant (P = 0.039). D-optimal design provided maximally informative sampling times for future pharmacokinetic studies. The pharmacokinetics of a conventional and an intermittently administered high-dose regimen liposomal amphotericin B are linear. Further pharmacokinetic-pharmacodynamic preclinical and clinical studies are required to identify safe and effective intermittent regimens.

    View details for DOI 10.1128/AAC.00933-12

    View details for Web of Science ID 000308807900041

    View details for PubMedID 22869566

  • Draft Genome Sequence of the Human Pathogen Halomonas stevensii S18214(T) JOURNAL OF BACTERIOLOGY Kim, K. K., Lee, K. C., Jeong, H., Stevens, D. A., Lee, J. 2012; 194 (18): 5143-5143

    Abstract

    Halomonas stevensii is a Gram-negative, moderately halophilic bacterium causing environmental contamination and infections in a dialysis center. Here we present the 3.7-Mb draft genome sequence of the type strain (S18214(T)) of H. stevensii, which will give insight into the pathogenic potential of H. stevensii.

    View details for DOI 10.1128/JB.01071-12

    View details for Web of Science ID 000308446100052

    View details for PubMedID 22933767

  • Experimental Central Nervous System Aspergillosis Therapy: Efficacy, Drug Levels and Localization, Immunohistopathology, and Toxicity. ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Clemons, K. V., Schwartz, J. A., Stevens, D. A. 2012; 56 (8): 4439-4449

    Abstract

    We have shown previously that high-dose lipid amphotericin preparations are not more efficacious than lower doses in aspergillosis. We studied toxicity, drug concentrations and localization, and quantitative infection concurrently, using a 4-day model of central nervous system (CNS) aspergillosis to assess early events. Mice given Aspergillus fumigatus conidia intracerebrally, under a cyclophosphamide immunosuppressive regimen, were treated for 3 days (AmBisome at 3 or 10 mg/kg of body weight, Abelcet at 10 mg/kg, amphotericin B deoxycholate at 1 mg/kg, caspofungin at 5 mg/kg, or voriconazole at 40 mg/kg). Sampling 24 h after the last treatment showed that AmBisome at 3 but not at 10 mg/kg, as well as Abelcet, caspofungin, and voriconazole, reduced brain CFU. All regimens reduced renal infection. Minor renal tubular changes occurred with AmBisome or Abelcet therapy, whereas heart, lung, and brain showed no drug toxicity. Amphotericin B tissue and serum concentrations did not correlate with efficacy. Endothelial cell activation (ICAM-1 and P-selectin in cerebral capillaries) occurred during infection. Amphotericin B derived from AmBisome and Abelcet localized in activated endothelium and from Abelcet in intravascular monocytes. In 10-day studies dosing uninfected mice, minor renal tubular changes occurred after AmBisome or Abelcet at 1, 5, or 10 mg/kg with or without cyclophosphamide treatment; nephrosis occurred only with Abelcet in cyclophosphamide-treated mice. Hepatotoxicity occurred with AmBisome and Abelcet but was reduced in cyclophosphamide-treated mice. Marked CFU reduction by AmBisome at 3 mg/kg occurred in association with relatively more intense inflammation. Abelcet renal localization appears to be a precursor to late nephrotoxicity. Hepatotoxicity may contribute to high-dose Abelcet and AmBisome failures. Our novel observation of endothelial amphotericin localization during infection may contribute to amphotericin mechanism of efficacy.

    View details for DOI 10.1128/AAC.06015-11

    View details for Web of Science ID 000306826300050

    View details for PubMedID 22687510

  • Orogastrointestinal model of mucosal and disseminated candidiasis. Methods in molecular biology (Clifton, N.J.) Clemons, K. V., Stevens, D. A. 2012; 845: 557-567

    Abstract

    Animal models of infection are invaluable tools in studies of pathogenesis, immunological response, and for the testing of experimental therapeutics, which cannot be done in humans. Murine models of infection are used most often for these studies and provide numerous advantages, including availability of immunological reagents, many strains with defined genetics, and ease of handling and cost considerations. Here we describe a model of orogastrointestinal candidiasis. Outbred mice are immunosuppressed using weekly doses of 5-fluorouracil to induce neutropenia and damage the mucosal epithelial layer, and are also maintained on a broad-spectrum antibiotic regimen to reduce secondary bacterial infection. Mice are infected orally to allow for the colonization of Candida albicans on the mucosal surfaces of the tongue, esophagus, stomach, small intestine, and cecum. Within 5 days, yeast disseminate from the gastrointestinal tract, to establish sites of infection in the kidneys and liver. Utilizing colony-forming units (CFU) recovered from specific tissues as the parameter for severity of infection, various therapeutic interventions can be examined for efficacy and capacity to eliminate colonization or disseminated infection. Studies of comparative virulence, host response, and pathogenesis are also possible using this model.

    View details for DOI 10.1007/978-1-61779-539-8_41

    View details for PubMedID 22328404

  • Saccharomyces as a Vaccine Against Systemic Candidiasis IMMUNOLOGICAL INVESTIGATIONS Liu, M., Clemons, K. V., Johansen, M. E., Martinez, M., Chen, V., Stevens, D. A. 2012; 41 (8): 847-855

    Abstract

    We have shown heat-killed Saccharomyces (HKY) is a protective vaccine against aspergillosis and coccidioidomycosis. To test the hypothesis that the efficacy of HKY- induced protection may be due to the cross-reactive antigens in the cell walls of the different fungi, we studied the effect of HKY against systemic candidiasis. Male CD-1 mice were given different regimens of HKY subcutaneously prior to intravenous challenge with Candida albicans. Compared to PBS controls, the administration of HKY (6 × 10(7)) 3, 4 or 6 times prolonged survival (all P < 0.05) and reduced fungal load in the kidney (all P < 0.05). An HKY dose of 1.2 × 10(8) given 4 times prolonged survival (P = 0.02), but showed dose-limiting toxicity. HKY given by an oral route, or by a subcutaneous route with alum as an adjuvant, did not improve survival. Overall, we found that HKY protects mice from infection by Candida albicans in a dose-and regimen-dependent manner. To understand the protection induced by HKY against different fungal species, additional studies of epitope mapping are warranted.

    View details for DOI 10.3109/08820139.2012.692418

    View details for Web of Science ID 000311897400004

    View details for PubMedID 22686468

  • Protein targets for broad-spectrum mycosis vaccines: quantitative proteomic analysis of Aspergillus and Coccidioides and comparisons with other fungal pathogens ADVANCES AGAINST ASPERGILLOSIS II Champer, J., Diaz-Arevalo, D., Champer, M., Hong, T. B., Wong, M., Shannahoff, M., Ito, J. I., Clemons, K. V., Stevens, D. A., Kalkum, M. 2012; 1273: 44-51

    Abstract

    Aspergillus species are responsible for most cases of fatal mold infections in immunocompromised patients, particularly in those receiving hematopoietic stem cell transplants. Experimental vaccines in mouse models have demonstrated a promising avenue of approach for the prevention of aspergillosis, as well as infections caused by other fungal pathogens, such as Coccidioides, the etiological agent of valley fever (coccidioidomycosis). Here, we investigated the hyphal proteomes of Aspergillus fumigatus and Coccidioides posadasii via quantitative MS(E) mass spectrometry with the objective of developing a vaccine that cross-protects against these and other species of fungi. Several homologous proteins with highly conserved sequences were identified and quantified in A. fumigatus and C. posadasii. Many abundant proteins from the cell wall of A. fumigatus present themselves as possible cross-protective vaccine candidates, due to the high degree of sequence homology to other medically relevant fungal proteins and low homologies to human or murine proteins.

    View details for DOI 10.1111/j.1749-6632.2012.06761.x

    View details for Web of Science ID 000312500200007

    View details for PubMedID 23230836

  • Influence of 17 beta-Estradiol on Gene Expression of Paracoccidioides during Mycelia-to-Yeast Transition PLOS ONE Shankar, J., Wu, T. D., Clemons, K. V., Monteiro, J. P., Mirels, L. F., Stevens, D. A. 2011; 6 (12)

    Abstract

    Paracoccidioides is the causative agent of paracoccidioidomycosis, a systemic mycosis endemic to Latin America. Infection is initiated by inhalation of conidia (C) or mycelial (M) fragments, which subsequently differentiate into yeast (Y). Epidemiological studies show a striking predominance of paracoccidioidomycosis in adult men compared to premenopausal women. In vitro and in vivo studies suggest that the female hormone (17?-estradiol, E(2)) regulates or inhibits M-or-C-to-Y transition. In this study we have profiled transcript expression to understand the molecular mechanism of how E(2) inhibits M-to-Y transition.We assessed temporal gene expression in strain Pb01 in the presence or absence of E(2) at various time points through 9 days of the M-to-Y transition using an 11,000 element random-shear genomic DNA microarray and verified the results using quantitative real time-PCR. E(2)-regulated clones were sequenced to identify genes and biological function.E(2)-treatment affected gene expression of 550 array elements, with 331 showing up-regulation and 219 showing down-regulation at one or more time points (p?0.001). Genes with low expression after 4 or 12 h exposure to E(2) belonged to pathways involved in heat shock response (hsp90 and hsp70), energy metabolism, and several retrotransposable elements. Y-related genes, ?-1,3-glucan synthase, mannosyltransferase and Y20, demonstrated low or delayed expression in E(2)-treated cultures. Genes potentially involved in signaling, such as palmitoyltransferase (erf2), small GTPase RhoA, phosphatidylinositol-4-kinase, and protein kinase (serine/threonine) showed low expression in the presence of E(2), whereas a gene encoding for an arrestin domain-containing protein showed high expression. Genes related to ubiquitin-mediated protein degradation, and oxidative stress response genes were up-regulated by E(2).This study characterizes the effect of E(2) at the molecular level on the inhibition of the M-to-Y transition and is indicative that the inhibitory actions of E(2) may be working through signaling genes that regulate dimorphism.

    View details for DOI 10.1371/journal.pone.0028402

    View details for Web of Science ID 000298369100035

    View details for PubMedID 22194832

  • Therapeutic and toxicologic studies in a murine model of invasive pulmonary aspergillosis MEDICAL MYCOLOGY Clemons, K. V., Schwartz, J. A., Stevens, D. A. 2011; 49 (8): 834-847

    Abstract

    Invasive pulmonary aspergillosis remains problematic in immunocompromised patient populations. We studied potential therapeutic options in a murine model of pulmonary aspergillosis in triamcinolone-suppressed DBA/2 mice infected intranasally with conidia from Aspergillus fumigatus. Mice were treated with liposomal-amphotericin B (AmBi; AmBisome), lipid-complexed amphotericin B (ABLC; Abelcet), voriconazole (VCZ), micafungin (MICA), caspofungin (CAS) or deoxycholate amphotericin B (AMBd) given alone or in combination. Monotherapy with AmBi, ABLC, AMBd, CAS or MICA had activity in prolonging survival; however, only AMBd or CAS reduced fungal burden in the lungs and kidneys. Combinations of AmBi plus CAS or MICA prolonged survival, but were not better than monotherapy. VCZ was ineffective and AMBd plus CAS showed a possible antagonism. AmBi or ABLC at higher dosages, or loading-doses of AmBi resulted in reduced survival. Histopathology showed increased incidence of serious renal and mild hepatic toxicity in triamcinolone-treated mice given an amphotericin B regimen compared to no or only triamcinolone (minimal renal changes occurred with CAS or VCZ with or without triamcinolone); suggestive of combined toxicity of triamcinolone and the amphotericin B in AmBi or ABLC. Infected treated mice showed progressive pulmonary disease including abscesses, angioinvasion and abundant intralesional fungi. High loading-doses of AmBi were associated with nephrosis and damage to other tissues. No monotherapy or combination regimen showed superiority for the treatment of pulmonary aspergillosis in corticosteroid suppressed mice and the potential for combined drug toxicity was enhanced in these mice. High dosages of lipid-formulated amphotericin B also proved unsatisfactory. Additional studies are needed to evaluate improved treatment.

    View details for DOI 10.3109/13693786.2011.577822

    View details for Web of Science ID 000295893300006

    View details for PubMedID 21539507

  • Diagnosing invasive fungal disease in critically ill patients CRITICAL REVIEWS IN MICROBIOLOGY Hsu, J. L., Ruoss, S. J., Bower, N. D., Lin, M., Holodniy, M., Stevens, D. A. 2011; 37 (4): 277-312

    Abstract

    Fungal infections are increasing, with a changing landscape of pathogens and emergence of new groups at risk for invasive disease. We review current diagnostic techniques, focusing on studies in critically ill patients. Microbiological cultures, the current "gold standard", demonstrate poor sensitivity, thus diagnosis of invasive disease in the critically ill is difficult. This diagnostic dilemma results in under- or over-treatment of patients, potentially contributing to poor outcomes and antifungal resistance. While other current diagnostic tests perform moderately well, many lack timeliness, efficacy, and are negatively affected by treatments common to critically ill patients. New nucleic acid-based research is promising.

    View details for DOI 10.3109/1040841X.2011.581223

    View details for Web of Science ID 000295616800001

    View details for PubMedID 21749278

  • Microsatellite multilocus genotyping clarifies the relationship of Candida parapsilosis strains involved in a neonatal intensive care unit outbreak DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE Vaz, C., Sampaio, P., Clemons, K. V., Huang, Y., Stevens, D. A., Pais, C. 2011; 71 (2): 159-162

    Abstract

    Microsatellite typing of 25 Candida parapsilosis isolates from a described outbreak in a neonatal intensive care showed 2 large groups of blood isolates that were related to hand isolates from specific hospital staff, not infant-colonizing isolates. These results demonstrate the power of this typing tool in clarifying epidemiologic associations.

    View details for DOI 10.1016/j.diagmicrobio.2011.05.014

    View details for Web of Science ID 000295425700011

    View details for PubMedID 21840674

  • Saccharomyces as a vaccine against systemic aspergillosis: 'the friend of man' a friend again? JOURNAL OF MEDICAL MICROBIOLOGY Liu, M., Capilla, J., Johansen, M. E., Alvarado, D., Martinez, M., Chen, V., Clemons, K. V., Stevens, D. A. 2011; 60 (10): 1423-1432

    Abstract

    The mortality of clinical Aspergillus infections necessitates consideration of the utility of a vaccine. We have found that Saccharomyces species can act as a protective vaccine against a lethal systemic Aspergillus infection, and describe experiments optimizing a subcutaneous regimen with killed yeast. Three injections of 2.5 mg given a week apart, 2 weeks prior to challenge, consistently, significantly, provided survival protection and reduction of infection in organs in survivors. The protection was independent of the strain of Saccharomyces, and possibly even the species, and could be demonstrated in several inbred (including C'-deficient) and outbred mouse strains. The protective moiety(ies) appeared to reside in the cell wall and was resistant to 100 °C, but not to protease or formalin. Alum potentiated the protection. The protection was comparable or superior to that of several Aspergillus-specific preparations described in the literature. Other studies have indicated that heat-killed Saccharomyces can protect against infection with at least three other fungal genera, raising the possibility of development of a panfungal vaccine, and such a vehicle has been studied in clinical trials, without dose-limiting toxicity.

    View details for DOI 10.1099/jmm.0.033290-0

    View details for Web of Science ID 000295860400002

    View details for PubMedID 21825307

  • Global population structure of Aspergillus terreus inferred by ISSR typing reveals geographical subclustering BMC MICROBIOLOGY Neal, C. O., Richardson, A. O., Hurst, S. F., Tortorano, A. M., Viviani, M. A., Stevens, D. A., Balajee, S. A. 2011; 11

    Abstract

    Aspergillus terreus causes invasive aspergillosis (IA) in immunocompromised individuals and can be the leading cause of IA in certain medical centers. We examined a large isolate collection (n = 117) for the presence of cryptic A. terreus species and employed a genome scanning method, Inter-Simple Sequence Repeat (ISSR) PCR to determine A. terreus population structure.Comparative sequence analyses of the calmodulin locus revealed the presence of the recently recognized species A. alabamensis (n = 4) in this collection. Maximum parsimony, Neighbor joining, and Bayesian clustering of the ISSR data from the 113 sequence-confirmed A. terreus isolates demonstrated that one clade was composed exclusively of isolates from Europe and another clade was enriched for isolates from the US.This study provides evidence of a population structure linked to geographical origin in A. terreus.

    View details for DOI 10.1186/1471-2180-11-203

    View details for Web of Science ID 000296005300001

    View details for PubMedID 21923908

  • Real-time PCR and quantitative culture for monitoring of experimental Aspergillus fumigatus intracranial infection in neutropenic mice JOURNAL OF MEDICAL MICROBIOLOGY Morton, C. O., Clemons, K. V., Springer, J., Mueller, J. G., Rogers, T. R., Stevens, D. A., Kurzai, O., Einsele, H., Loeffler, J. 2011; 60 (7): 913-919

    Abstract

    The central nervous system (CNS) is the most common site of dissemination during Aspergillus infection. PCR has the potential to facilitate early diagnosis of CNS aspergillosis, which could assist in reducing disease mortality. In two experiments, neutropenic CD-1 male mice were infected intracranially with 5×10? conidia of Aspergillus fumigatus. At time points up to 120 h after infection, mice were euthanized and samples of blood, brain, spinal cord and cerebrospinal fluid (CSF) were taken. The brain fungal burden was determined by quantitative culture, and fungal DNA was detected by quantitative PCR. Plating for A. fumigatus from the brain confirmed that all mice had burdens of log??>3 from 4 to 120 h after infection. A. fumigatus DNA was detected in blood (88?%), brain (96?%), CSF (52?%) and spinal cord (92?%) samples. The brain and spinal cord contained the highest concentrations of fungal DNA. Adapting the extraction protocol to maximize yield from small sample volumes (10 µl CSF or 200 µl blood) allowed PCR detection of A. fumigatus in infected mice, suggesting the use of CSF and blood as diagnostic clinical samples for CNS aspergillosis.

    View details for DOI 10.1099/jmm.0.028399-0

    View details for Web of Science ID 000292578700007

    View details for PubMedID 21436369

  • Pharmacokinetics of voriconazole in adult mallard ducks (Anas platyrhynchos) MEDICAL MYCOLOGY Kline, Y., Clemons, K. V., Woods, L., Stevens, D. A., Tell, L. A. 2011; 49 (5): 500-512

    Abstract

    The pharmacokinetics of voriconazole (VRC) administered intravenously (IV) or orally (PO; with and without liquid diet) to mallard ducks were studied. Dose range, drug bioavailability, and single and multiple treatment pharmacokinetics studies were performed. Plasma samples were collected for ultra performance liquid chromatography (UPLC) or bioassay analysis. Tissue samples were collected for high performance liquid chromatography (HPLC) analysis and histology. No overt signs of toxicity were observed during any of the studies regardless of administration route, and no histologic lesions/changes were attributed to VRC treatment. Average ± SD bioavailability after a single oral dose was 60.7% ± 16.5. Based on a targeted minimum inhibitory concentration of 0.5 ?g/ml VRC, a dose of 20 mg per kg body weight for the multi-dose pharmacokinetic study was selected. Pharmacokinetic parameter differences between birds dosed with VRC, with or without liquid diet, were not clinically significant. The bioassay had an overall positive bias (+23.5%) compared to the UPLC. Single or multiple-day VRC dosing via IV or PO routes at differing dosages resulted in tissue concentrations that were below the HPLC assay's limit of detection (0.1 ?g VRC per g tissue). This study indicates that treatment of mallard ducks with VRC might require a dosing interval of at least every 8-12 h at a dose of 20 mg/kg, but further studies are necessary.

    View details for DOI 10.3109/13693786.2010.542553

    View details for Web of Science ID 000291656000008

    View details for PubMedID 21171838

  • Hormones and the Resistance of Women to Paracoccidioidomycosis CLINICAL MICROBIOLOGY REVIEWS Shankar, J., Restrepo, A., Clemons, K. V., Stevens, D. A. 2011; 24 (2): 296-?

    Abstract

    Paracoccidioidomycosis, one of the most important endemic and systemic mycoses in Latin America, presents several clinical pictures. Epidemiological studies indicate a striking rarity of disease (but not infection) in females, but only during the reproductive years. This suggested a hormonal interaction between female hormones and the etiologic dimorphic fungus Paracoccidioides brasiliensis. Many fungi have been shown to use hormonal (pheromonal) fungal molecules for intercellular communication, and there are increasing numbers of examples of interactions between mammalian hormones and fungi, including the specific binding of mammalian hormones by fungal proteins, and suggestions of mammalian hormonal modulation of fungal behavior. This suggests an evolutionary conservation of hormonal receptor systems. We recount studies showing the specific hormonal binding of mammalian estrogen to proteins in P. brasiliensis and an action of estrogen to specifically block the transition from the saprophytic form to the invasive form of the fungus in vitro. This block has been demonstrated to occur in vivo in animal studies. These unique observations are consistent with an estrogen-fungus receptor-mediated effect on pathogenesis. The fungal genes responsive to estrogen action are under study.

    View details for DOI 10.1128/CMR.00062-10

    View details for Web of Science ID 000289346500004

    View details for PubMedID 21482727

  • Immune responses induced by heat killed Saccharomyces cerevisiae: A vaccine against fungal infection VACCINE Liu, M., Clemons, K. V., Bigos, M., Medovarska, I., Brummer, E., Stevens, D. A. 2011; 29 (9): 1745-1753

    Abstract

    Heat-killed Saccharomyces cerevisiae (HKY) used as a vaccine protects mice against systemic aspergillosis and coccidioidomycosis. Little is known about the immune response induced by HKY vaccination, consequently our goal was to do an analysis of HKY-induced immune responses involved in protection. BALB/c mice were vaccinated subcutaneously 3 times with HKY, a protective reagent, and bronchoalveolar lavage fluid, spleen, lymph nodes, and serum collected 2-5 weeks later. Cultured spleen or lymph node cells were stimulated with HKY. Proliferation of HKY-stimulated spleen or lymph node cells was tested by Alamar Blue reduction and flow cytometry. Cytokines from lymphocyte supernatants and antibody to glycans in serum collected from HKY-vaccinated mice were measured by ELISA. The results show that HKY promoted spleen cell and lymph node cell proliferation from HKY-vaccinated mice but not from PBS-vaccinated control mice (all P<0.05). Cytokine measurement showed HKY significantly promoted IFN?, IL-6 and IL-17A production by spleen cells and lymph node cells (all P<0.05 and P<0.01, respectively). Cytokine production by HKY-stimulated cells from PBS-vaccinated mice was lower than those from HKY-vaccinated (P<0.05). Cytokines in BAL from HKY-vaccinated were higher, 1.7-fold for IFN? and 2.1-fold for TNF?, than in BAL from PBS-vaccinated. Flow cytometry of lymphocytes from HKY-vaccinated showed 52% of CD3(+) or 56% of CD8(+) cells exhibited cell division after stimulation with HKY, compared to non-stimulated controls (26 or 23%, respectively) or HKY-stimulated cells from PBS-vaccinated (31 or 34%). HKY also induced antibody against Saccharomyces glucan and mannan with titers 4- or 2-fold, respectively, above that in unvaccinated. Taken together, the results suggested that HKY vaccination induces significant and specific Th1 type cellular immune responses and antibodies to glucan and mannan.

    View details for DOI 10.1016/j.vaccine.2010.12.119

    View details for Web of Science ID 000288058500004

    View details for PubMedID 21219976

  • Aspergillus Vertebral Osteomyelitis in Immunocompetent Hosts: Role of Triazole Antifungal Therapy CLINICAL INFECTIOUS DISEASES Studemeister, A., Stevens, D. A. 2011; 52 (1)

    Abstract

    A review of published cases, in addition to a recently treated patient, is presented that describes the clinical features and outcomes of triazole therapy for vertebral aspergillosis in immunocompetent patients.Using the Medline database, cases of vertebral aspergillosis in immunocompetent patients treated with triazole were reviewed. Clinical and radiological findings, therapeutic interventions, and outcomes were analyzed. RESULTS.: Twenty-one cases of vertebral aspergillosis treated with itraconazole or voriconazole were identified. Most cases were caused by Aspergillus fumigatus. The most common presenting symptom was back pain. The majority of cases were acquired by hematogenous infection, although one-quarter occurred after a spinal procedure. Most patients were treated successfully with a combination of antifungal therapy and surgery. Patients presenting with paraplegia had a poor outcome. The overall mortality rate was 20%.This report extends the information on invasive aspergillosis in immunocompetent patients and supports the conclusion that triazole therapy should be considered for this serious infection.

    View details for DOI 10.1093/cid/ciq039

    View details for Web of Science ID 000286214200026

    View details for PubMedID 21148508

  • Aspergillosis in the 'Nonimmunocompromised' Host IMMUNOLOGICAL INVESTIGATIONS Stevens, D. A., Melikian, G. L. 2011; 40 (7-8): 751-766

    Abstract

    Invasive aspergillosis has been classically associated with certain risk factors: cytotoxic chemotherapy, prolonged neutropenia, corticosteroids, transplantation, AIDS. However, the literature is growing that this mycosis, particularly pulmonary aspergillosis, can be seen in patients lacking these factors. Many of the latter patients are in the intensive care unit. Other associated conditions include influenza, nonfungal pneumonia, chronic obstructive lung disease, immaturity, sepsis, liver failure, alcoholism, chronic granulomatous disease and surgery. Certain focal sites, such as sinusitis or cerebral aspergillosis, have additional risk factors. This emphasizes the potential importance of a positive culture for Aspergillus in the critically ill, the need for awareness about possible aspergillosis in patients lacking the classical risk factors, and readiness to proceed with appropriate diagnostic maneuvers.

    View details for DOI 10.3109/08820139.2011.614307

    View details for Web of Science ID 000295693100007

    View details for PubMedID 21985304

  • An Official American Thoracic Society Statement: Treatment of Fungal Infections in Adult Pulmonary and Critical Care Patients AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Limper, A. H., Knox, K. S., Sarosi, G. A., Ampel, N. M., Bennett, J. E., Catanzaro, A., Davies, S. F., Dismukes, W. E., Hage, C. A., Marr, K. A., Mody, C. H., Perfect, J. R., Stevens, D. A. 2011; 183 (1): 96-128

    Abstract

    With increasing numbers of immune-compromised patients with malignancy, hematologic disease, and HIV, as well as those receiving immunosupressive drug regimens for the management of organ transplantation or autoimmune inflammatory conditions, the incidence of fungal infections has dramatically increased over recent years. Definitive diagnosis of pulmonary fungal infections has also been substantially assisted by the development of newer diagnostic methods and techniques, including the use of antigen detection, polymerase chain reaction, serologies, computed tomography and positron emission tomography scans, bronchoscopy, mediastinoscopy, and video-assisted thorascopic biopsy. At the same time, the introduction of new treatment modalities has significantly broadened options available to physicians who treat these conditions. While traditionally antifungal therapy was limited to the use of amphotericin B, flucytosine, and a handful of clinically available azole agents, current pharmacologic treatment options include potent new azole compounds with extended antifungal activity, lipid forms of amphotericin B, and newer antifungal drugs, including the echinocandins. In view of the changing treatment of pulmonary fungal infections, the American Thoracic Society convened a working group of experts in fungal infections to develop a concise clinical statement of current therapeutic options for those fungal infections of particular relevance to pulmonary and critical care practice. This document focuses on three primary areas of concern: the endemic mycoses, including histoplasmosis, sporotrichosis, blastomycosis, and coccidioidomycosis; fungal infections of special concern for immune-compromised and critically ill patients, including cryptococcosis, aspergillosis, candidiasis, and Pneumocystis pneumonia; and rare and emerging fungal infections.

    View details for DOI 10.1164/rccm.2008-740ST

    View details for Web of Science ID 000286155600016

    View details for PubMedID 21193785

  • Efficacy of Recombinant Human Mannose Binding Lectin Alone and in Combination with Itraconazole Against Murine Candida albicans vaginitis IMMUNOLOGICAL INVESTIGATIONS Clemons, K. V., Martinez, M., Axelsen, M., Thiel, S., Stevens, D. A. 2011; 40 (6): 553-568

    Abstract

    Mannan binding lectin (MBL) deficiency has been associated with increased susceptibility to vaginitis in humans due to Candida albicans. In these studies we assessed the utility of recombinant human MBL (rhMBL) as a therapeutic against experimental C. albicans vaginitis. After intravenous treatment of uninfected mice with 75 ?g of rhMBL, rhMBL was detected in the serum and peritoneal lavage fluid; rhMBL was detected in the serum of infected mice 2 and 24 hours post-dose, and at very low concentrations in vaginal lavage fluid. Intravenous treatment with rhMBL alone or in combination with oral itraconazole enhanced the clearance of C. albicans from the vagina of wild-type or MBL gene knockout (KO) mice; rhMBL was modestly effective alone. However, rhMBL in combination with itraconazole was not better than itraconazole alone. Topical administration of rhMBL in a cream appeared more effective than rhMBL in a gel and both were inferior to commercial clotrimazole cream. Topical rhMBL cream in combination with itraconazole resulted in a 3-fold improvement in clearance of the yeast compared with sole itraconazole therapy. Overall, these data indicate that rhMBL may have utility in the treatment of candidal vaginitis when used as an adjunctive therapy.

    View details for DOI 10.3109/08820139.2011.569627

    View details for Web of Science ID 000291946400001

    View details for PubMedID 21510780

  • Molecular epidemiology of Saccharomyces cerevisiae in an immunocompromised host unit DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE Clemons, K. V., Salonen, J. H., Issakainen, J., Nikoskelainen, J., McCullough, M. J., Jorge, J. J., Stevens, D. A. 2010; 68 (3): 220-227

    Abstract

    Saccharomyces cerevisiae is increasingly recognized clinically, and repeated isolations from patients on a hematology unit in Turku, Finland, led to an epidemiologic investigation. Isolates were recovered from multiple body sites of 23 patients (n = 180) from 1994 to 1995 and from 29 patients (n = 45) from 1997 to 2002; these plus 2 from the hospital kitchen were identified as S. cerevisiae. Isolates were genotyped by restriction fragment length polymorphism (RFLP) of genomic DNA after EcoR1 digestion. Of 108 isolates, 97 (95 patient isolates and 2 from the hospital kitchen) were DNA group B and identical in RFLP pattern. The remaining 11 isolates were DNA group A; 2 patients that shared a room had identical group A isolates, both converted to DNA group B type colonization within 2 months. In almost all patients, S. cerevisiae was first recovered after admission. These data suggest an endemic source of colonizing organisms, possibly from the hospital food preparation area.

    View details for DOI 10.1016/j.diagmicrobio.2010.06.010

    View details for Web of Science ID 000283833100005

    View details for PubMedID 20846806

  • Immunomodulatory effects of antifungal agents on the response of human monocytic cells to Aspergillus fumigatus conidia MEDICAL MYCOLOGY Choi, J., Kwon, E., Park, C., Choi, S., Lee, D., Yoo, J., Shin, W., Stevens, D. A. 2010; 48 (5): 704-709

    Abstract

    We evaluated the immunomodulatory effects of three different classes of antifungal agents on the human monocytic cell line, THP-1, which had been stimulated in vitro with Aspergillus fumigatus conidia. Cells treated with amphotericin B (AmB), micafungin (MF), and voriconazole (VCZ), at concentrations not affecting cell viability, reduced production of tumor necrosis factor (TNF)-alpha in response to conidia, with the greatest reduction noted with VCZ. The reduction of TNF-alpha production correlated with TNF-alpha gene expression assessed by PCR and nuclear factor kappaB (NF kappaB) levels. Co-stimulation with granulocyte-macrophage colony stimulating factor abolished immunomodulatory effects of the drugs. Antifungal agents affect the immune reaction caused by A. fumigatus conidia in stimulated monocytes at clinically relevant drug concentrations. Because drugs with different mechanisms of action produced this effect, this suggests that it is the result of factors mediated by the cells. The impact of these immunomodulatory effects needs assessment.

    View details for DOI 10.3109/13693780903471784

    View details for Web of Science ID 000280700800004

    View details for PubMedID 20156030

  • Effect of 3M-003, an imidazoquinoline, on phagocyte candidacidal activity directly and via induction of peripheral blood mononuclear cell cytokines FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY Brummer, E., Antonysamy, M. A., Bythadka, L., Gullikson, G. W., Stevens, D. A. 2010; 59 (1): 81-89

    Abstract

    3M-003, like related imidazoquinoline immunomodulators, interacts with Toll-like receptor-7 (TLR-7) and TLR-8. TLRs are important in the defense against fungal pathogens. The effect of 3M-003 on killing of Candida was evaluated on mouse (BALB/c) effector cell lineages: monocytes, neutrophils, and macrophages. After direct application, 3M-003 (1-80 microg mL(-1)) enhanced (P<0.05-0.01) macrophage killing, comparable to killing by interferon-gamma-activated macrophages. 3M-003 did not directly enhance the candidacidal activity of monocytes or neutrophils. To test an effect mediated by leukocytes, BALB/c peripheral blood mononuclear cells (PBMC) were stimulated in vitro with 3M-003 to generate cytokine-containing supernatants. 3M-003 at 1 or 3 microM was optimal for the stimulation of PBMC to produce tumor necrosis factor-alpha and interleukin-12p40 in 24 h. For indirect tests, monolayers were treated with supernatants for 18 h, the supernatants were removed, and effector cells were tested; the supernatants enhanced (P<0.05-0.01) killing, in 2-4-h assays, by neutrophils from 42% to 73%, macrophages from 0% to 23%, and monocytes from 0% to 20%. 3M-003, presumably through TLRs, acts directly on macrophages to enhance fungal killing and stimulates PBMC to produce soluble factors that enhance killing by neutrophils, macrophages, and monocytes. 3M-003 could be a candidate for antifungal immunotherapy.

    View details for DOI 10.1111/j.1574-695X.2010.00664.x

    View details for Web of Science ID 000277321600009

    View details for PubMedID 20337703

  • New Polymorphic Microsatellite Markers Able To Distinguish among Candida parapsilosis Sensu Stricto Isolates JOURNAL OF CLINICAL MICROBIOLOGY Sabino, R., Sampaio, P., Rosado, L., Stevens, D. A., Clemons, K. V., Pais, C. 2010; 48 (5): 1677-1682

    Abstract

    Among the Candida species causing bloodstream infections, Candida parapsilosis is one of the most frequently isolated. The objective of the present work was the identification of new microsatellite loci able to distinguish among C. parapsilosis isolates. DNA sequences with trinucleotide repeats were selected from the C. parapsilosis genome database. PCR primer sets flanking the microsatellite repeats were designed and tested with 20 independent isolates. On the basis of the amplification efficiency, specificity, and observed polymorphism, four of the sequences were selected for strain typing. Two hundred thirty-three independent C. parapsilosis sensu stricto isolates were genotyped by using these markers. The polymorphic loci exhibited from 20 to 42 alleles and 39 to 92 genotypes. In a multiplex analysis, 192 genotypes were obtained and the combined discriminatory power of the four microsatellites was 0.99. Reproducibility was demonstrated by submission of subcultures of 4 isolates each, in triplicate, interspersed with unique numbers among a group of 30 isolates for blind testing. Comparison of the genotypes obtained by microsatellite analysis and those obtained by randomly amplified polymorphic DNA analysis, restriction fragment length polymorphism analysis, and internal transcribed sequence grouping was performed and showed that the microsatellite method could distinguish individual isolates; none of the other methods could do that. Related species, C. orthopsilosis and C. metapsilosis, were not confused with C. parapsilosis sensu stricto. These new microsatellites are a valuable tool for use for the differentiation of C. parapsilosis sensu stricto strains, vital in epidemiology to answer questions of strain relatedness and determine pathways of transmission.

    View details for DOI 10.1128/JCM.02151-09

    View details for Web of Science ID 000277356600025

    View details for PubMedID 20220157

  • Itraconazole, a Commonly Used Antifungal that Inhibits Hedgehog Pathway Activity and Cancer Growth CANCER CELL Kim, J., Tang, J. Y., Gong, R., Kim, J., Lee, J. J., Clemons, K. V., Chong, C. R., Chang, K. S., Fereshteh, M., Gardner, D., Reya, T., Liu, J. O., Epstein, E. H., Stevens, D. A., Beachy, P. A. 2010; 17 (4): 388-399

    Abstract

    In a screen of drugs previously tested in humans we identified itraconazole, a systemic antifungal, as a potent antagonist of the Hedgehog (Hh) signaling pathway that acts by a mechanism distinct from its inhibitory effect on fungal sterol biosynthesis. Systemically administered itraconazole, like other Hh pathway antagonists, can suppress Hh pathway activity and the growth of medulloblastoma in a mouse allograft model and does so at serum levels comparable to those in patients undergoing antifungal therapy. Mechanistically, itraconazole appears to act on the essential Hh pathway component Smoothened (SMO) by a mechanism distinct from that of cyclopamine and other known SMO antagonists, and prevents the ciliary accumulation of SMO normally caused by Hh stimulation.

    View details for DOI 10.1016/j.ccr.2010.02.027

    View details for Web of Science ID 000276879700010

    View details for PubMedID 20385363

  • Efficacy of voriconazole in Japanese quail (Coturnix japonica) experimentally infected with Aspergillus fumigatus MEDICAL MYCOLOGY Tell, L. A., Clemons, K. V., Kline, Y., Woods, L., Kass, P. H., Martinez, M., Stevens, D. A. 2010; 48 (2): 234-244

    Abstract

    Aspergillus fumigatus causes disease in birds. Our objectives were to determine pharmacokinetic parameters and evaluate efficacy of voriconazole (VCZ) in a novel experimental quail model. After a single oral VCZ dose of 20 or 40 mg/kg, plasma concentrations peaked 2 h postdose (5.8 and 6.9 microg/ml) and remained above 0.5 microg/ml for 4 and 12 h postdose, respectively. For the efficacy study, ten-day-old Japanese quail (n = 60) were infected intratracheally with A. fumigatus conidia. Daily oral VCZ at 20 or 40 mg/kg was initiated 24 h postinfection (PI); infected diluent-treated birds were given de-ionized water orally. Preassigned birds were euthanized on days 5 or 10 PI. VCZ at 40 mg/kg prolonged survival compared to 20 mg/kg or diluent-treatment (P < 0.05) and lungs from birds given VCZ at 40 mg/kg had fewer colony forming units (CFU) than diluent-treated (P = 0.03). At day 10 PI, birds treated with VCZ at 20 mg/kg had significantly fewer fungi in the lungs as demonstrated by methenamine silver stain (P = 0.017) or immunohistochemistry, as compared to diluent-treated (P = 0.034). Histopathologically, VCZ-treated birds did not have necrotic lesions and showed a trend toward fewer with acute inflammatory changes. VCZ at 40 mg/kg was efficacious in quail with experimental pulmonary aspergillosis.

    View details for DOI 10.3109/13693780903008821

    View details for Web of Science ID 000274879300003

    View details for PubMedID 19548171

  • Resistance of MBL gene-knockout mice to experimental systemic aspergillosis IMMUNOLOGY LETTERS Clemons, K. V., Martinez, M., Tong, A., Stevens, D. A. 2010; 128 (2): 105-107

    Abstract

    Mannose binding lectin (MBL) is a protein of the collectin family that appears important in resistance to invasive pulmonary aspergillosis. We assessed the role of MBL in experimental systemic aspergillosis. MBL-sufficient C57BL/6 (WT) mice and B6.129S4--Mb11(tm1Kata) Mb12(tm1Kata)/J MBL A and C gene-knockout (KO) mice were infected intravenously with different inocula of Aspergillus fumigatus conidia. WT and KO mice were dose-responsively susceptible. In no instance were the KO mice more susceptible than WT. At the highest inoculum, all WT and 90% of KO mice died on day 4 (P>0.05). Reduction of the inoculum to 5.5 x 10(6) conidia was lethal, but comparison showed KO mice less susceptible to lethal infection (P<0.015). At the lowest inoculum used, deaths of KO mice were delayed, but survival was not significantly different than WT (P>0.05). These results suggest MBL may play a deleterious role in systemic aspergillosis.

    View details for DOI 10.1016/j.imlet.2009.12.021

    View details for Web of Science ID 000275526700003

    View details for PubMedID 20064561

  • Collectins and fungal pathogens: roles of surfactant proteins and mannose binding lectin in host resistance MEDICAL MYCOLOGY Brummer, E., Stevens, D. A. 2010; 48 (1): 16-28

    Abstract

    Collectins, collagenous carbohydrate-binding proteins (C-type lectins), are recognized as important factors in non-specific innate immune responses to pathogens. By binding surface carbohydrate structures of pathogens, collectins modify the interaction between pathogens and the immune system. We review the structure of the lung surfactant proteins (SP) SP-A and SP-D, and the serum collectins, mannose binding lectins; the binding of these collectins to pathogen associated molecular patterns or ligands on pathogenic fungi; and the effect of collectin binding to opportunistic and primary fungal pathogens on the interaction with host defense cells, which can result in enhancement or inhibition of resistance. The result of collectin binding to opportunistic fungal pathogens (Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Pneumocystis) or primary fungal pathogens (Blastomyces dermatitidis, Coccidioides, Histoplasma capsulatum, Paracoccidioides brasiliensis) on interaction with host defense cells relative to complement fixation, phagocytosis, and stimulation of cytokine/chemokine production is reviewed. Increased understanding of these relationships in future will help understand fungal pathogenesis and host defenses against mycoses.

    View details for DOI 10.3109/13693780903117473

    View details for Web of Science ID 000274739900002

    View details for PubMedID 19639514

  • Correlation of restriction fragment length polymorphism genotyping with internal transcribed spacer sequence, randomly amplified polymorphic DNA and multilocus sequence groupings for Candida parapsilosis MYCOSES van Asbeck, E. C., Clemons, K. V., Markham, A. N., Stevens, D. A. 2009; 52 (6): 493-498

    Abstract

    Epidemiological studies of Candida parapsilosis have been performed by molecular methods. To compare two prominent methods, 29 isolates, typed by multilocus sequence typing (MLST), were typed by restriction fragment length polymorphism (RFLP). Of the 19 proposed Candida parapsilosis sensu stricto isolates [group I by internally transcribed spacer (ITS1) sequence], the most commonly encountered species, 17 were RFLP type VII-1. The species Candida orthopsilosis (eight isolates) and Candida metapsilosis (two isolates) consisted of five and one other RFLP types, respectively; none were VII-1. None of the non-VII-1 types were in more than one ITS group. VII-1 is the most common RFLP type (176/203 in continuing studies), and C. parapsilosis sensu stricto is similarly dominant in other studies, and cannot be subtyped by RFLP or MLST. RFLP subtype VII-1 and C. parapsilosis sensu stricto appear to be nearly identical; C. orthopsilosis, which can be subtyped by MLST, can also be subtyped by RFLP. C. metapsilosis appears rarely.

    View details for DOI 10.1111/j.1439-0507.2008.01649.x

    View details for Web of Science ID 000270589000004

    View details for PubMedID 19207835

  • A safety and feasibility study comparing an intermittent high dose with a daily standard dose of liposomal amphotericin B for persistent neutropenic fever JOURNAL OF MEDICAL MICROBIOLOGY Ellis, M., Bernsen, R., Ali-Zadeh, H., Kristensen, J., Hedstrom, U., Poughias, L., Bresnik, M., Al-Essa, A., Stevens, D. A. 2009; 58 (11): 1474-1485

    Abstract

    A high intermittent dose regimen (group A: 10 mg kg(-1) on day 1, 5 mg kg(-1) on days 3 and 6) was compared with standard dosing (group B: 3 mg kg(-1) per day for 14 days) of liposomal amphotericin B (LAB) for empirical treatment of persistent febrile neutropenia. A total cumulative dose of 1275 mg (group A) and 2800 mg (group B) was administered. Infusion-related adverse drug events, mainly rigors/chills, occurred more frequently with group A (11/45, 24 % infusions) than with group B (12/201, 6 % infusions) (P=0.002), which extended the mean infusion time by 20 min (P=0.001). Creatinine levels were similar in the two regimens: the A : B ratio of the area under the curve for creatinine (AUC(CREATININE)) for days 2-7 was 1.09 (P=0.27) and for days 2-14 was 1.05 (P=0.51). Rises in creatinine were mild (clinical toxicity criteria 1) in all patients with elevations. Hypokalaemia tended to be less severe in group A with a lower proportion of hypokalaemic days [57/143 (39 %) vs 80/137 (58 %), P=0.21], a higher AUC(POTASSIUM) (A : B ratio of 1.06, P=0.12), a lower proportion of patients with hypokalaemia at the end of study (10 vs 61 %, P=0.01) and fewer potassium-supplemented days [12/210 (6 %) vs 41/210 (19.5 %), P<0.1]. There were mildly elevated median levels of serum bilirubin, alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase, which were similar for the two regimens and were usually associated with other co-existing co-morbid conditions. The AUC for these enzymes was also similar in the two groups. No patient had discontinuation of the study drug due to toxicity. Composite success was identical for each regimen (11/15 patients, 73 %). Three of the fifteen patients in group B and none in group A developed invasive fungal infections (IFIs). Beta-D-Glucan levels were similar in both groups for patients without an IFI [AUC(GLUCAN) of 362 and 683 (P=0.36) for groups A and B, respectively]. The rate of defervescence was similar for each regimen (P=0.75). This feasibility study suggests that a short intermittent high-dose course of 10/5/5 mg LAB kg(-1) on days 1, 3 and 6 may be as safe and effective as a standard 14 day course of 3 mg kg(-1) per day, with drug-acquisition cost savings and reduced drug exposure. A larger study is indicated for confirmation of this.

    View details for DOI 10.1099/jmm.0.012401-0

    View details for Web of Science ID 000271440200011

    View details for PubMedID 19589901

  • Expert Opinion: What To Do When There Is Coccidioides Exposure in a Laboratory CLINICAL INFECTIOUS DISEASES Stevens, D. A., Clemons, K. V., Levine, H. B., Pappagianis, D., Baron, E. J., Hamilton, J. R., Deresinski, S. C., Johnson, N. 2009; 49 (6): 919-923

    Abstract

    Inadvertent exposure to Coccidioides species by laboratory staff and others as a result of a mishap is not an uncommon cause of infection in clinical microbiology laboratories. These types of infection may occur in laboratories outside the endemic areas, because the etiologic agent is unexpected in the submitted specimens and because personnel may be unfamiliar with the hazards of dealing with Coccidioides species in the laboratory. Coccidioidal infections are often difficult to treat, and outcomes can be poor. Here, we emphasize prevention and an approach to a laboratory accident that minimizes the risk of exposure to laboratory staff and staff in adjacent areas. On the basis of an artificially large exposure to arthroconidia that may occur as a result of a laboratory accident, a conservative approach of close observation and early treatment of exposed staff is discussed.

    View details for DOI 10.1086/605441

    View details for Web of Science ID 000269145100014

    View details for PubMedID 19663562

  • Genomic DNA microarray comparison of gene expression patterns in Paracoccidioides brasiliensis mycelia and yeasts in vitro MICROBIOLOGY-SGM Monteiro, J. P., Clemons, K. V., Mirels, L. F., Coller, J. A., Wu, T. D., Shankar, J., Lopes, C. R., Stevens, D. A. 2009; 155: 2795-2808

    Abstract

    Paracoccidioides brasiliensis is a thermally dimorphic fungus, and causes the most prevalent systemic mycosis in Latin America. Infection is initiated by inhalation of conidia or mycelial fragments by the host, followed by further differentiation into the yeast form. Information regarding gene expression by either form has rarely been addressed with respect to multiple time points of growth in culture. Here, we report on the construction of a genomic DNA microarray, covering approximately 25 % of the genome of the organism, and its utilization in identifying genes and gene expression patterns during growth in vitro. Cloned, amplified inserts from randomly sheared genomic DNA (gDNA) and known control genes were printed onto glass slides to generate a microarray of over 12,000 elements. To examine gene expression, mRNA was extracted and amplified from mycelial or yeast cultures grown in semi-defined medium for 5, 8 and 14 days. Principal components analysis and hierarchical clustering indicated that yeast gene expression profiles differed greatly from those of mycelia, especially at earlier time points, and that mycelial gene expression changed less than gene expression in yeasts over time. Genes upregulated in yeasts were found to encode proteins shown to be involved in methionine/cysteine metabolism, respiratory and metabolic processes (of sugars, amino acids, proteins and lipids), transporters (small peptides, sugars, ions and toxins), regulatory proteins and transcription factors. Mycelial genes involved in processes such as cell division, protein catabolism, nucleotide biosynthesis and toxin and sugar transport showed differential expression. Sequenced clones were compared with Histoplasma capsulatum and Coccidioides posadasii genome sequences to assess potentially common pathways across species, such as sulfur and lipid metabolism, amino acid transporters, transcription factors and genes possibly related to virulence. We also analysed gene expression with time in culture and found that while transposable elements and components of respiratory pathways tended to increase in expression with time, genes encoding ribosomal structural proteins and protein catabolism tended to sharply decrease in expression over time, particularly in yeast. These findings expand our knowledge of the different morphological forms of P. brasiliensis during growth in culture.

    View details for DOI 10.1099/mic.0.027441-0

    View details for Web of Science ID 000269028900033

    View details for PubMedID 19406900

  • Halomonas, a Newly Recognized Human Pathogen Causing Infections and Contamination in a Dialysis Center Three New Species MEDICINE Stevens, D. A., Hamilton, J. R., Johnson, N., Kim, K. K., Lee, J. 2009; 88 (4): 244-249

    Abstract

    Our Renal Care Center (RCC) is a separate building, performing almost 2500 outpatient dialysis runs per month. In May 2007, 2 patients developed, days apart, bacteremia with an apparently identical nonfermentative Gram-negative rod. Because of difficulty identifying the organism, testing in the Biolog system identified them as a Halomonas species. Sequencing of approximately 1500 bases of the 16S rRNA gene in both organisms in 3 reference laboratories confirmed, searching against 3 databases, that the organisms were identical and were Halomonas species. There were 54 recognized species of this genus, associated with marine or saline sites. Initial attempts at environmental isolation as primary cultures, including a 4% salt agar plate, or initial incubation in 6.5% salt broth enrichment culture with subculture to agar, to exploit the halophilicity of Halomonas, were successful in demonstrating the colonies seen in the blood cultures, only from sites not contaminated with other organisms, because of competing growth. A more selective method was developed for use on samples suspected to be heavily contaminated with other organisms, using the strategy of increased salt concentration in a broth enrichment culture to further exploit Halomonas halotolerance, and thereby inhibit other organisms. A 16.5% salt concentration in brain-heart infusion broth, incubated at 35 degrees C for 48-72 hours, then subcultured to agar plates incubated in room air at 35 degrees C, proved optimal for selection and secondary isolation. With a combination of these techniques, 14/15 cultures of dialysates and 10/38 from the outflow pathways of the machines were Halomonas positive, compared to 0/31 cultures from the inflow side of the machines (including water supplies and storing, mixing, and preparation tanks). The exception was sites associated with or downstream of bicarbonate influx, 12/54 of which were positive. Two other local hospitals' dialysis centers, and our own inpatient dialysis facility, were cultured at sites that yielded Halomonas from our RCC, and Halomonas was not isolated. Further study by 16S rRNA gene sequencing and DNA-DNA hybridization revealed the cultures represented 3 novel species: 1 (H. stevensii sp. nov.) in the patients and environment and 2 (H. hamiltonii sp. nov., H. johnsoniae sp. nov.) in the environment, most closely related to H. magadiensis. Of 35 speciated isolates, 22 were H. stevensii, 10 H. johnsoniae, and 3 H. hamiltonii. We hypothesize that the RCC became contaminated with these halophilic organisms from bicarbonate used to prepare dialysis fluid, and they persist despite cleaning and flushing procedures because of biofilm in machines and bicarbonate fluid inflow sites. Our experience, together with the review of the literature presented here, indicates the genus Halomonas has pathogenic potential.

    View details for DOI 10.1097/MD.0b013e3181aede29

    View details for Web of Science ID 000268079000008

    View details for PubMedID 19593230

  • A New Method for the Treatment of Chronic Fungal Meningitis: Continuous Infusion into the Cerebrospinal Fluid for Coccidioidal Meningitis AMERICAN JOURNAL OF THE MEDICAL SCIENCES Berry, C. D., Stevens, D. A., Hassid, E. I., Pappagianis, D., Happs, E. L., Sahrakar, K. 2009; 338 (1): 79-82

    Abstract

    Coccidioidal meningitis is a lethal disease, and current therapy is not curative or is burdened with serious toxicities and logistic difficulties. In a patient with refractory disease, continuous infusion amphotericin B therapy was given via a programmable implanted pump into the cisternal subarachnoid space. The patient progressively responded, evidenced clinically and by laboratory studies. Drug delivery issues were addressed during this course that could guide future use of this modality, which is a promising novel avenue of therapy for chronic meningitis.

    View details for Web of Science ID 000268147700021

    View details for PubMedID 19506457

  • Saccharomyces cerevisiae as a vaccine against coccidioidomycosis VACCINE Capilla, J., Clemons, K. V., Liu, M., Levine, H. B., Stevens, D. A. 2009; 27 (27): 3662-3668

    Abstract

    Disseminated coccidioidomycosis is a life-threatening infection. In these studies, we examined protection against systemic murine coccidioidomycosis by vaccination with heat-killed Saccharomyces cerevisiae (HKY). CD-1 mice received HKY subcutaneously or by oral gavage with or without adjuvants once weekly beginning 3 or 4 weeks prior to infection; oral live Saccharomyces was also studied. All HKY sc regimens were equivalent, prolonging survival (P

    View details for DOI 10.1016/j.vaccine.2009.03.030

    View details for Web of Science ID 000267459900022

    View details for PubMedID 19464548

  • Frequency of paradoxical effect with caspofungin in Candida albicans EUROPEAN JOURNAL OF CLINICAL MICROBIOLOGY & INFECTIOUS DISEASES Stevens, D. A. 2009; 28 (6): 717-717

    View details for DOI 10.1007/s10096-008-0688-y

    View details for Web of Science ID 000266372700026

    View details for PubMedID 19130103

  • Comparative Efficacies of Lipid-Complexed Amphotericin B and Liposomal Amphotericin B against Coccidioidal Meningitis in Rabbits ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Clemons, K. V., Capilla, J., Sobel, R. A., Martinez, M., Tong, A., Stevens, D. A. 2009; 53 (5): 1858-1862

    Abstract

    In separate previous studies, we have shown that lipid-complexed amphotericin B (Abelcet [ABLC]) and liposomal amphotericin B (AmBisome [AmBi]) are efficacious against coccidioidal meningitis in rabbits. Here, we compared ABLC and AmBi directly in a coccidioidal meningitis model. Male New Zealand White rabbits were infected with 5 x 10(4) Coccidioides posadasii arthroconidia by direct cisternal puncture. Therapy with intravenous ABLC or AmBi at 7.5 or 15 mg/kg of body weight or sterile 5% dextrose water (D5W) began 5 days later. Clinical assessments were done daily; cerebrospinal fluid and blood samples were obtained on day 15 and upon euthanasia. Survivors to day 25 were euthanatized, the numbers of CFU in their tissues were determined, and histology analyses of the brains and spinal cords were done. Controls showed progressive disease, whereas animals treated with either dose of either drug showed few clinical signs of infection. All ABLC- or AmBi-treated rabbits survived, whereas eight of nine D5W-treated rabbits were euthanatized before day 25 (P < 0.0001). Numbers of CFU in the brains and spinal cords of ABLC- or AmBi-treated animals were 100- to 10,000-fold lower than those in the corresponding tissues of D5W-treated animals (P < 0.0006 to 0.0001). However, only two or fewer given a regimen of ABLC or AmBi were cured of infection in both tissues. Fewer ABLC-treated rabbits (four of eight treated with 7.5 mg/kg and five of eight treated with 15 mg/kg) than controls (nine of nine) had meningitis at any level of severity (P, 0.015 or 0.043 for animals treated with ABLC at 7.5 or 15 mg/kg, respectively). Although groups of rabbits treated with AmBi regimens did not have significantly fewer animals with meningitis than the control group (P > 0.05), ABLC and AmBi were not significantly different. In this model, intravenous ABLC and AmBi were similarly highly effective, with few clinical signs of infection, 100% survival, and significantly reduced fungal burdens among treated animals. There appeared to be little benefit in using the 15-mg/kg dosage of either formulation. There was no significant advantage of one drug over the other for this indication. Further studies are required to determine the lowest effective doses of these formulations.

    View details for DOI 10.1128/AAC.01538-08

    View details for Web of Science ID 000265528700019

    View details for PubMedID 19273680

  • Candida parapsilosis: a review of its epidemiology, pathogenesis, clinical aspects, typing and antimicrobial susceptibility CRITICAL REVIEWS IN MICROBIOLOGY van Asbeck, E. C., Clemons, K. V., Stevens, D. A. 2009; 35 (4): 283-309

    Abstract

    The Candida parapsilosis family has emerged as a major opportunistic and nosocomial pathogen. It causes multifaceted pathology in immuno-compromised and normal hosts, notably low birth weight neonates. Its emergence may relate to an ability to colonize the skin, proliferate in glucose-containing solutions, and adhere to plastic. When clusters appear, determination of genetic relatedness among strains and identification of a common source are important. Its virulence appears associated with a capacity to produce biofilm and production of phospholipase and aspartyl protease. Further investigations of the host-pathogen interactions are needed. This review summarizes basic science, clinical and experimental information about C. parapsilosis.

    View details for DOI 10.3109/10408410903213393

    View details for Web of Science ID 000275267300002

    View details for PubMedID 19821642

  • Clinical aspergillosis for basic scientists MEDICAL MYCOLOGY Stevens, D. A. 2009; 47: S1-S4

    Abstract

    Aspergilli are ubiquitous, and can cause a variety of allergic disorders and invasive infections. These various manifestations of the diseases, diagnosis and treatment are organized for basic scientists, so that they may better understand the dimensions and nature of the clinical challenges.

    View details for DOI 10.1080/13693780802322232

    View details for Web of Science ID 000265362300001

    View details for PubMedID 18720215

  • Conventional or molecular measurement of Aspergillus load MEDICAL MYCOLOGY Clemons, K. V., Stevens, D. A. 2009; 47: S132-S137

    Abstract

    The quantification of organisms is a standard tool. Measurement of a hyphal organism, like Aspergillus, presents difficulties in that it is problematic to define what constitutes a cell. Growth occurs by hyphal tip extension, in which the hypha elongates and a septum is formed behind the tip to divide it in to a separate compartment. However, communication between compartments and streaming of nuclei makes defining a cell of a hyphal organism difficult and the best method for quantification of the hyphal organism remains controversial. Conventional CFU determination of fungal burden in tissue homogenates is readily done by most laboratories, but CFU recovered temporally tend to show minimal increase, and may indicate that mechanical homogenization does not cause significant fragmentation of the hyphae in the tissues. Does the lack of increase in CFU as infection worsens inadequately reflect fungal load in the tissue? Non-culture based assays including chitin determination, quantitative PCR and enzyme immunoassay (EIA) of cell wall constituents, galactomannan or beta-glucan overcome this difficulty in part. However, qPCR and EIA do not indicate viability, may result in false negatives. qPCR assay may represent a significant over-estimation, because it correlates with number of nuclei present; it also requires specialized equipment and reagents. Temporal studies of infection have demonstrated that qPCR and to some extent EIA reflect an increase in fungal burden not shown by CFU. Although qPCR and CFU may not correlate in those types of studies, comparative studies have shown CFU and qPCR do correlate when determining antifungal drug efficacy, where each method can clearly demonstrate differences in fungal burden; EIA methods have also been shown to reflect this difference. Overall, there remains no optimal, single method for determination of fungal load of Aspergillus and it may be that a combination of methods (e.g., CFU and qPCR) should be used.

    View details for DOI 10.1080/13693780802213340

    View details for Web of Science ID 000265362300018

    View details for PubMedID 18654916

  • Molecular epidemiology of global Candida dubliniensis isolates utilizing genomic-wide, co-dominant, PCR-based markers for strain delineation MEDICAL MYCOLOGY McCullough, M. J., Hepworth, G., Gordon, I., Clemons, K. V., Stevens, D. A. 2009; 47 (8): 789-795

    Abstract

    The molecular epidemiology of Candida dubliniensis has been studied using large complex DNA probes for Southern analysis and has revealed the existence of distinct genotypes within this species. The aim of the present study was to utilize a PCR-based analysis of molecular co-dominant markers to assess the relatedness of a global and temporally diverse collection of well characterized isolates of C. dubliniensis. Sixty-two C. dubliniensis strains were collected from the authors of previously published studies. Co-dominant PCR-based markers utilizing five separate PCR fingerprints were obtained in the present investigation. Phylogenetic and statistical analyses utilizing permutation tests were undertaken to assess correlations amongst the isolates. Three distinct PCR-groups were observed and there was evidence that strains isolated since 1990 were genotypically more similar to each other than they were to strains recovered prior to 1990.

    View details for DOI 10.3109/13693780802641912

    View details for Web of Science ID 000273003600002

    View details for PubMedID 19353373

  • In Vitro Activity of Amphotericin B Against Aspergillus terreus Isolates from Different Countries and Regions JOURNAL OF CHEMOTHERAPY Tortorano, A. M., Prigitano, A., Dho, G., Biraghi, E., Stevens, D. A., Ghannoum, M., Nolard, N., Viviani, M. A. 2008; 20 (6): 756-757

    View details for Web of Science ID 000262764100016

    View details for PubMedID 19129077

  • Significant differences in drug susceptibility among species in the Candida parapsilosis group DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE van Asbeck, E., Clemons, K. V., Martinez, M., Tong, A., Stevens, D. A. 2008; 62 (1): 106-109

    Abstract

    Candida parapsilosis family has 3 proposed species: C. parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis. C. parapsilosis sensu stricto had significantly higher caspofungin (CAS) and anidulafungin MICs than C. orthopsilosis or C. metapsilosis; C. metapsilosis was least susceptible to fluconazole. C. parapsilosis sensu stricto more frequently displayed (37%) paradoxical growth in CAS (P < or = 0.02). These species susceptibility differences could affect therapeutic choices.

    View details for DOI 10.1016/j.diagmicrobio.2008.04.019

    View details for Web of Science ID 000258994000018

    View details for PubMedID 18555634

  • Defining responses to therapy and study outcomes in clinical trials of invasive fungal diseases: Mycoses study group and European Organization for Research and Treatment of Cancer consensus criteria CLINICAL INFECTIOUS DISEASES Segal, B. H., Herbrecht, R., Stevens, D. A., Ostrosky-Zeichner, L., Sobel, J., Viscoli, C., Walsh, T. J., Maertens, J., Patterson, T. F., Perfect, J. R., Dupont, B., Wingard, J. R., Calandra, T., Kauffman, C. A., Graybill, J. R., Baden, L. R., Pappas, P. G., Bennett, J. E., Kontoyiannis, D. P., Cordonnier, C., Viviani, M. A., Bille, J., Almyroudis, N. G., Wheat, L. J., Graninger, W., Bow, E. J., Holland, S. M., Kullberg, B., Dismukes, W. E., de Pauw, B. E. 2008; 47 (5): 674-683

    Abstract

    Invasive fungal diseases (IFDs) have become major causes of morbidity and mortality among highly immunocompromised patients. Authoritative consensus criteria to diagnose IFD have been useful in establishing eligibility criteria for antifungal trials. There is an important need for generation of consensus definitions of outcomes of IFD that will form a standard for evaluating treatment success and failure in clinical trials. Therefore, an expert international panel consisting of the Mycoses Study Group and the European Organization for Research and Treatment of Cancer was convened to propose guidelines for assessing treatment responses in clinical trials of IFDs and for defining study outcomes. Major fungal diseases that are discussed include invasive disease due to Candida species, Aspergillus species and other molds, Cryptococcus neoformans, Histoplasma capsulatum, and Coccidioides immitis. We also discuss potential pitfalls in assessing outcome, such as conflicting clinical, radiological, and/or mycological data and gaps in knowledge.

    View details for DOI 10.1086/590566

    View details for Web of Science ID 000258181000013

    View details for PubMedID 18637757

  • A possible mechanism for synergy between antifungal therapy and immune defenses JOURNAL OF INFECTIOUS DISEASES Stevens, D. A. 2008; 198 (2): 159-162

    View details for DOI 10.1086/589306

    View details for Web of Science ID 000257320400002

    View details for PubMedID 18500932

  • Revised definitions of invasive fungal disease from the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) Consensus Group CLINICAL INFECTIOUS DISEASES de Pauw, B., Walsh, T. J., Donnelly, J. P., Stevens, D. A., Edwards, J. E., Calandra, T., Pappas, P. G., Maertens, J., Lortholary, O., Kauffman, C. A., Denning, D. W., Patterson, T. F., Maschmeyer, G., Bille, J., Dismukes, W. E., Herbrecht, R., Hope, W. W., Kibbler, C. C., Kullberg, B. J., Marr, K. A., Munoz, P., Odds, F. C., Perfect, J. R., Restrepo, A., Ruhnke, M., Segal, B. H., Sobel, J. D., Sorrell, T. C., Viscoli, C., Wingard, J. R., Zaoutis, T., Bennett, J. E. 2008; 46 (12): 1813-1821

    Abstract

    Invasive fungal diseases are important causes of morbidity and mortality. Clarity and uniformity in defining these infections are important factors in improving the quality of clinical studies. A standard set of definitions strengthens the consistency and reproducibility of such studies.After the introduction of the original European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) Consensus Group definitions, advances in diagnostic technology and the recognition of areas in need of improvement led to a revision of this document. The revision process started with a meeting of participants in 2003, to decide on the process and to draft the proposal. This was followed by several rounds of consultation until a final draft was approved in 2005. This was made available for 6 months to allow public comment, and then the manuscript was prepared and approved.The revised definitions retain the original classifications of "proven," "probable," and "possible" invasive fungal disease, but the definition of "probable" has been expanded, whereas the scope of the category "possible" has been diminished. The category of proven invasive fungal disease can apply to any patient, regardless of whether the patient is immunocompromised, whereas the probable and possible categories are proposed for immunocompromised patients only.These revised definitions of invasive fungal disease are intended to advance clinical and epidemiological research and may serve as a useful model for defining other infections in high-risk patients.

    View details for DOI 10.1086/588660

    View details for Web of Science ID 000256044900007

    View details for PubMedID 18462102

  • Comparison of lipid amphotericin B preparations in treating murine zygomycosis ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Ibrahim, A. S., Gebremariam, T., Husseiny, M. I., Stevens, D. A., Fu, Y., Edwards, J. E., Spellberg, B. 2008; 52 (4): 1573-1576

    Abstract

    We compared the efficacies of liposomal amphotericin B (LAmB) and an amphotericin B lipid complex (ABLC) in diabetic ketoacidotic (DKA) or neutropenic mice with disseminated zygomycosis. ABLC was as effective as LAmB in neutropenic but not DKA mice. Low-dose ABLC was less effective than LAmB at reducing brain fungal burdens in both models.

    View details for DOI 10.1128/AAC.01488-07

    View details for Web of Science ID 000254881900063

    View details for PubMedID 18227182

  • Evasion of innate immune responses: Evidence for mannose binding lectin inhibition of tumor necrosis factor alpha production by macrophages in response to Blastomyces dennatitidis INFECTION AND IMMUNITY Koneti, A., Linke, M. J., Brummer, E., Stevens, D. A. 2008; 76 (3): 994-1002

    Abstract

    Serum factors, including mannose binding lectins (MBL), influence innate responses to microbes. Little is known about the effects of serum factors or MBL on the interaction of Blastomyces dermatitidis, a pulmonary fungal pathogen, with macrophages or on tumor necrosis factor alpha (TNF-alpha) production. Since macrophage production of TNF-alpha is an important innate immune response, we examined a mouse peritoneal macrophage (PM) cell line (RAW) and resident PM from CD-1 mice to study TNF-alpha production by PM stimulated with heat-killed (HK) or live B. dermatitidis yeast cells. Mouse serum and heat-inactivated mouse serum inhibited TNF-alpha production 94% when macrophages were stimulated by B. dermatitidis, whereas mouse immunoglobulin G (IgG) did not have this effect. HK B. dermatitidis incubated with serum and then washed also failed to stimulate significant TNF-alpha production by PM. By the sandwich immunofluorescent antibody (IFA) method with anti-mouse MBL (MBL-A or -C), we showed that serum MBL bound to B. dermatitidis. When serum was absorbed with HK B. dermatitidis or live B. dermatitidis, absorbed serum failed to significantly inhibit TNF-alpha production by RAW cells plus B. dermatitidis, and immunoblotting showed that absorbed serum was depleted of MBL-C. If serum was absorbed with live B. dermatitidis, unbound serum was eluted, and bound serum factor(s) (BS) was released with guanidine buffer, BS inhibited TNF-alpha production by PM plus B. dermatitidis in a concentration-dependent manner. BS contained MBL-C, which bound B. dermatitidis, as shown by IFA assay. 1,3-beta-Glucan stimulated TNF-alpha production by PM, and this was inhibited by mouse serum. Treatment of B. dermatitidis with anti-1,3-beta-glucan antibody inhibited TNF-alpha production by PM. With anti-1,3-beta-glucan antibody, we showed by IFA assay that B. dermatitidis contained 1,3-beta-glucan. In an IFA study with B. dermatitidis, serum with an anti-mouse IgG conjugate did not result in fluorescence, yet serum blocked IFA staining of B. dermatitidis by anti-1,3-beta-glucan IgG antibody. This indicated that non-IgG serum factors binding to B. dermatitidis prevented access to 1,3-beta-glucan by anti-1,3-beta-glucan antibody. These results suggest that the mechanism of inhibition of the innate proinflammatory immune response of PM to B. dermatitidis is mediated by serum MBL binding to B. dermatitidis at 1,3-beta-glucan sites or sterically masking 1,3-beta-glucan sites, thus preventing 1,3-beta-glucan stimulation of PM for TNF-alpha production.

    View details for DOI 10.1128/IAI.01185-07

    View details for Web of Science ID 000253563500016

    View details for PubMedID 18070904

  • Treatment of aspergillosis: Clinical practice guidelines of the infectious diseases society of America CLINICAL INFECTIOUS DISEASES Walsh, T. J., Anaissie, E. J., Denning, D. W., Herbrecht, R., Kontoyiannis, D. P., Marr, K. A., Morrison, V. A., Segal, B. H., Steinbach, W. J., Stevens, D. A., van Burik, J., Wingard, J. R., Patterson, T. F. 2008; 46 (3): 327-360

    View details for DOI 10.1086/525258

    View details for Web of Science ID 000252221200001

    View details for PubMedID 18177225

  • Molecular epidemiology of the global and temporal diversity of Candida parapsilosis SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES van Asbeck, E. C., Clemons, K. V., Markham, A. N., Stevens, D. A. 2008; 40 (10): 827-834

    Abstract

    We examined the global epidemiology of C. parapsilosis and assessed the discriminatory capabilities of restriction fragment length polymorphism (RFLP) and RAPD typing methods. We used EcoRI digestion of cellular DNA to generate RFLP; RAPD analysis on genomic DNA. Band profiles were used to distinguish and group isolates. From 7 diverse geographic areas, 536 isolates obtained over 35 y were placed into 23 RFLP subgroups. Subtype VII-1 was dominant worldwide (82.4% of isolates). Dividing the isolates into VII-1 versus non-VII-1 showed temporal variation for the USA pre-1995 versus post-1995 (p<0.0001) and versus Europe pre-1995 (p<0.0001). Genotype distribution differed among localities (p<0.0001); Mexico was unique (p<0.05) due to the high proportion of non-VII-1. The prevalence of C. parapsilosis RFLP type VII-1 apparently has risen in the USA and current isolates show some variation in distribution of types in some non-USA localities. There were no differences in distribution of types comparing babies versus adults, or bloodstream isolates versus colonizing or environmental isolates. RAPD typing showed 3 major profiles, but was less discriminatory.

    View details for DOI 10.1080/00365540802144133

    View details for Web of Science ID 000259239700010

    View details for PubMedID 18609202

  • Candida parapsilosis fungemia in neonates: genotyping results suggest healthcare workers hands as source, and review of published studies MYCOPATHOLOGIA van Asbeck, E. C., Huang, Y., Markham, A. N., Clemons, K. V., Stevens, D. A. 2007; 164 (6): 287-293

    Abstract

    An outbreak of Candida parapsilosis fungemia involving 17 neonatal intensive care unit (NICU) patients was studied. There were 14 blood culture and nine colonizing isolates from other sites available. The hands of NICU healthcare workers (HCW) yielded eight isolates. Screening of the isolates by random amplified polymorphic DNA (RAPD) method showed only three profiles. Typing by restriction fragment length polymorphism (RFLP) revealed all blood isolates were RFLP subtype VII-1. Among the nine infant colonizing isolates, there were four different RFLP subtypes; four of the isolates were subtype VII-1. Seven of the eight isolates from HCW were RFLP subtype VII-1. The majority of infant colonizers were not found in the blood, suggesting a possible direct spread of the epidemic subtype VII-1 strain from HCW hands to infant blood. The source of the infant colonizing strains is unclear, but non-VII-1 strains may be largely of maternal origin and VII-1 strains from HCW. These findings reinforce prior studies that have implicated HCW hands as the source of nosocomial, including neonatal, fungemia.

    View details for DOI 10.1007/s11046-007-9054-3

    View details for Web of Science ID 000250308200005

    View details for PubMedID 17874281

  • Animal models: an important tool in mycology MEDICAL MYCOLOGY Capilla, J., Clemons, K. V., Stevens, D. A. 2007; 45 (8): 657-684

    Abstract

    Animal models of fungal infections are, and will remain, a key tool in the advancement of the medical mycology. Many different types of animal models of fungal infection have been developed, with murine models the most frequently used, for studies of pathogenesis, virulence, immunology, diagnosis, and therapy. The ability to control numerous variables in performing the model allows us to mimic human disease states and quantitatively monitor the course of the disease. However, no single model can answer all questions and different animal species or different routes of infection can show somewhat different results. Thus, the choice of which animal model to use must be made carefully, addressing issues of the type of human disease to mimic, the parameters to follow and collection of the appropriate data to answer those questions being asked. This review addresses a variety of uses for animal models in medical mycology. It focuses on the most clinically important diseases affecting humans and cites various examples of the different types of studies that have been performed. Overall, animal models of fungal infection will continue to be valuable tools in addressing questions concerning fungal infections and contribute to our deeper understanding of how these infections occur, progress and can be controlled and eliminated.

    View details for DOI 10.1080/13693780701644140

    View details for Web of Science ID 000252219400001

    View details for PubMedID 18027253

  • Efficacy of amphotericin B lipid complex in a rabbit model of coccidioidal meningitis JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY Capilla, J., Clemons, K. V., Sobel, R. A., Stevens, D. A. 2007; 60 (3): 673-676

    Abstract

    We compared the efficacy of treatments in a rabbit model of coccidioidal meningitis (CM).Rabbits were infected intracisternally with Coccidioides immitis and treated with intravenous amphotericin B lipid complex (ABLC), deoxycholate amphotericin B (dAMB), oral fluconazole or diluent [sterile 5% dextrose in water (D5W)]. Survival and cfu in brain, spinal cord and CSF were determined and histology studied. Amphotericin B (AMB) concentrations in serum, CSF and tissue were determined by bioassay.Fluconazole-treated rabbits and controls lost weight and had decreased mobility. All treatments prolonged survival (P = 0.005) and reduced cfu in brain and spinal cord (P

    View details for DOI 10.1093/jac/dkm264

    View details for Web of Science ID 000249882200035

    View details for PubMedID 17646202

  • Safety, tolerance, and efficacy of posaconazole therapy in patients with nonmeningeal disseminated or chronic pulmonary coccidioidomycosis CLINICAL INFECTIOUS DISEASES Catanzaro, A., Cloud, G. A., Stevens, D. A., Levine, B. E., Williams, P. L., Johnson, R. H., Rendon, A., Mirels, L. F., Lutz, J. E., Holloway, M., Galgiani, J. N. 2007; 45 (5): 562-568

    Abstract

    Coccidioidomycosis can be difficult to treat with available therapies, particularly in patients with progressive or disseminated disease. Posaconazole is a new azole antifungal with potent activity against Coccidioides species, the causative agent of coccidioidomycosis.Twenty patients with chronic pulmonary or nonmeningeal disseminated coccidioidomycosis were enrolled in a multicenter trial to study the safety and tolerability of posaconazole therapy, with efficacy as a secondary end point. Patients received posaconazole (400 mg/day) in capsule formulation for up to 6 months. Safety was evaluated on the basis of the occurrence of adverse events. A satisfactory efficacy response was defined as a >or=50% reduction in the Mycoses Study Group score from baseline.Seventeen (85%) of 20 patients had a satisfactory response to treatment. The median duration of treatment was 173 days. Paired baseline and end-of-treatment culture results for Coccidioides species were available for 4 patients, all of whom converted from being positive to being negative for Coccidioides species. Relapse was experienced by 3 of 9 patients who did not receive antifungal therapy during the follow-up period. In general, posaconazole therapy was well tolerated, with 12 of 20 patients reporting adverse events that were possibly or probably related to treatment. The most common adverse events were dry mouth (in 5 patients [25%]) and headache (in 3 patients [15%]).Courses of posaconazole therapy that were up to 6 months in duration were well tolerated in patients with coccidioidomycosis. Although this study was limited by the number of patients enrolled, it clearly demonstrates that posaconazole shows promise in the treatment of patients with coccidioidomycosis and warrants additional investigation in a full-scale clinical trial.

    View details for DOI 10.1086/519937

    View details for Web of Science ID 000248557000015

    View details for PubMedID 17682989

  • Posaconazole therapy for chronic refractory coccidioidomycosis CHEST Stevens, D. A., Rendon, A., Gaona-Flores, V., Catanzaro, A., Anstead, G. M., Pedicone, L., Graybill, J. R. 2007; 132 (3): 952-958

    Abstract

    Coccidioides infections often result in chronic relapsing disease that presents a challenge to the currently available therapy. Posaconazole, an oral extended-spectrum triazole agent, has been shown in vitro and in vivo to have potent activity against this fungus.An open-label multinational study of posaconazole, 800 mg/d, administered in divided doses for the treatment of invasive fungal infection that has been refractory to previous therapy was conducted. The data were reviewed by an independent data review committee (DRC). Fifteen patients met the criteria for proven coccidioidal infection and disease refractory to previous therapy. Success was a complete or partial response; nonsuccess was stable disease, lack of response to therapy, or undetermined response.The sites of coccidioidal infection were pulmonary (seven patients) and disseminated (eight patients). Patients were refractory to previous therapy (including amphotericin B with or without an azole) for a median duration of 306 days. At the end of treatment (posaconazole treatment duration, 34 to 365 days), therapy for 11 of 15 patients (73%) was considered to be successful by the DRC. Four responses were complete and seven were partial; these included five patients with pulmonary sites and six patients with disseminated sites. In responders, improvement was seen within months of the initiation of therapy. Five patients received therapy for >or= 12 months. The side effects were minimal.Therapy for coccidioidomycosis remains a clinical challenge, especially when patients have not responded to therapy with drugs that were recommended in treatment guidelines. The success rate (73%) achieved in this case series suggests that oral posaconazole should be considered as an important agent for the treatment of refractory coccidioidomycosis.

    View details for DOI 10.1378/chest.07-0114

    View details for Web of Science ID 000249742100036

    View details for PubMedID 17573510

  • Production of IL-6, in contrast to other cytokines and chemokines, in macrophage innate immune responses: Effect of serum and fungal (Blastomyces) challenge CYTOKINE Brummer, E., Capilla, J., Bythadka, L., Stevens, D. A. 2007; 39 (3): 163-170

    Abstract

    Murine peritoneal macrophages, after adherence and establishment in culture in vitro in the presence of medium containing fetal bovine serum (FBS) for 20 h, then cultured for 20 h, produced several cytokines. If, in the second 20 h period, a fungus (heat-killed Blastomyces, HK-Bd) was introduced, a more complex pattern of cytokine (particularly TNF) and chemokine production ensued. The cytokine production, assayed by antibody array and also quantitation in supernatants, was depressed (particularly TNF) by the addition of mouse serum to these cultures, with the exception of IL-6. Macrophages could be cultured in the presence or absence of serum during the initial 20 h adherence and establishment period, enabling study of the effect of serum factors. In the absence of serum, with or without fungal stimulation, cytokine and chemokine production was more restricted, largely to TNF and IL-6. The addition of mouse serum [corrected] resulted in marked depression of TNF and enhancement of IL-6. The combination of HK-Bd and mouse serum resulted in more IL-6 production than either component alone. The enhancement of IL-6 by mouse serum was concentration-dependent and maximal at 8 h. The effects of fungus or serum on macrophage production of cytokines were similar in an outbred and an inbred mouse strain. The larger repertoire of cytokine production in the macrophages that had been cultured longer (20 h+20 h) in serum may be related to maturation of cell receptors. IL-6 production in vivo in response to fungal-serum complexes could affect pathogenesis by opposing the host defense modulation by proinflammatory cytokines or by modulating the destructive effects of inflammation on host tissues.

    View details for DOI 10.1016/j.cyto.2007.07.001

    View details for Web of Science ID 000251151000002

    View details for PubMedID 17716906

  • Comparison of itraconazole and fluconazole treatments in a murine model of coccidioidal meningitis ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Kamberi, P., Sobel, R. A., Clemons, K. V., Waldvogel, A., Striebel, J. M., Williams, P. L., Stevens, D. A. 2007; 51 (3): 998-1003

    Abstract

    Coccidioidal meningitis (CM) is a devastating disease that requires long-term therapy and for which there is little hope of a cure. A model was used to compare the efficacies of itraconazole and fluconazole. CD-1 mice were infected intrathecally with 30 to 36 viable arthroconidia of Coccidioides. Oral therapy with cyclodextrin (control) or itraconazole or fluconazole at 10, 25, or 50 mg/kg of body weight twice daily (BID) was given for 12 days, from day 3 of infection. Treatment with both antifungals at all doses prolonged survival compared with that of the control treatment (P < 0.01 to 0.0001). At 50 mg/kg, itraconazole and fluconazole were equivalent, whereas itraconazole at 10 or 25 mg/kg prolonged survival compared to that achieved with fluconazole at these dosages (P < 0.05 and 0.01, respectively). Early histologic analysis (10 days of treatment) with 50 mg/kg BID itraconazole or fluconazole showed suppression of CM in all five animals per group; in quantitative cultures, three of three animals from each group had no detectable infection in the brain, spinal cord, or a site of secondary infection, the lungs. In contrast, four of seven controls showed mild to severe meningitis, with arteritis detected in three animals. In a short-term organ clearance study, 5 days of treatment with 10 or 50 mg/kg BID itraconazole or fluconazole reduced the tissue burdens in the brain and spinal cord compared to the tissue burdens in the controls (P < 0.02 to 0.0003). Fluconazole at 10 mg/kg did not reduce the fungal burden in secondary sites, the lungs and kidneys, whereas this itraconazole dose was more effective in clearing the fungi from both organs (P < 0.05 and P < 0.001, respectively). At 50 mg/kg, itraconazole and fluconazole were equivalent in clearing the fungi from the brain and kidney, but itraconazole was superior to fluconazole in clearing the fungi from the spinal cord and lungs (P < 0.05). Thus, both itraconazole and fluconazole were effective at controlling CM, but neither eliminated Coccidioides from tissues. Overall, itraconazole was more efficacious on an mg/kg basis; at high doses they were similarly effective.

    View details for DOI 10.1128/AAC.00332-06

    View details for Web of Science ID 000244665500028

    View details for PubMedID 17178793

  • Azole therapy of clinical and experimental coccidioidomycosis COCCIDIOIDOMYCOSIS: SIXTH INTERNATIONAL SYMPOSIUM Stevens, D. A., Clemons, K. V. 2007; 1111: 442-454

    Abstract

    The therapy of coccidioidomycosis has been an early target, both experimentally and clinically, for study of new members of the azole class of drugs, because of the recognition that coccidioidomycosis is one of the most difficult mycoses to treat, and because our research group and our collaborators have been eager to pioneer new therapies for this problem pathogen. There have been steady advances in the pharmacologic and antimicrobial properties of this class since the initial introduction of miconazole, and many patients with coccidioidomycosis have benefited. Perhaps the greatest contribution has been the development of well-tolerated oral drugs that make possible prolonged courses of a conveniently administered agent, and perhaps the most impressive advance has been the utility of the agents in coccidioidal meningitis, at least as an adjunct to the polyenes. More potent agents are still required, so that complete biological cure can be attained in meningeal and nonmeningeal coccidioidomycosis.

    View details for DOI 10.1196/annals.1406.039

    View details for Web of Science ID 000250750700039

    View details for PubMedID 17344535

  • Treatment of invasive aspergillosis with posaconazole in patients who are refractory to or intolerant of conventional therapy: An externally controlled trial CLINICAL INFECTIOUS DISEASES Walsh, T. J., Raad, I., Patterson, T. F., Chandrasekar, P., Donowitz, G. R., Graybill, R., Greene, R. E., Hachem, R., Hadley, S., Herbrecht, R., Langston, A., Louie, A., Ribaud, P., Segal, B. H., Stevens, D. A., van Burik, J. H., White, C. S., Corcoran, G., Gogate, J., Krishna, G., Pedicone, L., Hardalo, C., Perfect, J. R. 2007; 44 (1): 2-12

    Abstract

    Invasive aspergillosis is an important cause of morbidity and mortality in immunocompromised patients. Current treatments provide limited benefit. Posaconazole is an extended-spectrum triazole with in vitro and in vivo activity against Aspergillus species.We investigated the efficacy and safety of posaconazole oral suspension (800 mg/day in divided doses) as monotherapy in an open-label, multicenter study in patients with invasive aspergillosis and other mycoses who were refractory to or intolerant of conventional antifungal therapy. Data from external control cases were collected retrospectively to provide a comparative reference group.Cases of aspergillosis deemed evaluable by a blinded data review committee included 107 posaconazole recipients and 86 control subjects (modified intent-to-treat population). The populations were similar and balanced with regard to prespecified demographic and disease variables. The overall success rate (i.e., the data review committee-assessed global response at the end of treatment) was 42% for posaconazole recipients and 26% for control subjects (odds ratio, 4.06; 95% confidence interval, 1.50-11.04; P=.006). The differences in response between the modified intent-to-treat treatment groups were preserved across additional, prespecified subsets, including infection site (pulmonary or disseminated), hematological malignancy, hematopoietic stem cell transplantation, baseline neutropenia, and reason for enrollment (patient was refractory to or intolerant of previous antifungal therapy). An exposure-response relationship was suggested by pharmacokinetic analyses.Although the study predates extensive use of echinocandins and voriconazole, these findings demonstrate that posaconazole is an alternative to salvage therapy for patients with invasive aspergillosis who are refractory to or intolerant of previous antifungal therapy.

    View details for Web of Science ID 000242479500001

    View details for PubMedID 17143808

  • Experimental animal models of coccidioidomycosis COCCIDIOIDOMYCOSIS: SIXTH INTERNATIONAL SYMPOSIUM Clemons, K. V., Capilla, J., Stevens, D. A. 2007; 1111: 208-224

    Abstract

    Experimental models of coccidioidomycosis performed using various laboratory animals have been, and remain, a critical component of elucidation and understanding of the pathogenesis and host resistance to infection with Coccidioides spp., as well as to development of more efficacious antifungal therapies. The general availability of genetically defined strains, immunological reagents, ease of handling, and costs all contribute to the use of mice as the primary laboratory animal species for models of this disease. Five types of murine models are studied and include primary pulmonary disease, intraperitoneal with dissemination, intravenous infection emulating systemic disease, and intracranial or intrathecal infection emulating meningeal disease. Each of these models has been used to examine various aspects of host resistance, pathogenesis, or antifungal therapy. Other rodent species, such as rat, have been used much less frequently. A rabbit model of meningeal disease, established by intracisternal infection, has proven to model human meningitis well. This model is useful in studies of host response, as well as in therapy studies. A variety of other animal species including dogs, primates, and guinea pigs have been used to study host response and vaccine efficacy. However, cost and increased needs of animal care and husbandry are limitations that influence the use of the larger animal species.

    View details for DOI 10.1196/annals.1406.029

    View details for Web of Science ID 000250750700017

    View details for PubMedID 17344524

  • Experimental systemic infection with Cryptococcus neoformas var. grubii and Cryptococcus gattii in normal and immunodeficient mice MEDICAL MYCOLOGY Capilla, J., Maffei, C. M., Clemons, K. V., Sobel, R. A., Stevens, D. A. 2006; 44 (7): 601-610

    Abstract

    Cryptococcus neoformans (Cn) var. grubii or Cryptococcus neoformans var. neoformans infection is usually associated with immunocompromised hosts, whereas Cryptococcusgattii more frequently causes disease in immunocompetent hosts. We examined the effects of immunodeficiency and glucocorticoid-induced immunosuppression on systemic murine infection induced by i.v. inoculation with these pathogens. SCID and immunocompetent BALB/c and C57BL/6 mice were infected with

    View details for DOI 10.1080/13693780600810040

    View details for Web of Science ID 000242552000003

    View details for PubMedID 17071553

  • Interferon- gamma as an antifungal. journal of infectious diseases Stevens, D. A., Brummer, E., Clemons, K. V. 2006; 194: S33-7

    View details for PubMedID 16921470

  • Escape of Candida from caspofungin inhibition at concentrations above the MIC (Paradoxical effect) accomplished by increased cell wall chitin; Evidence for beta-1,6-glucan synthesis inhibition by caspofungin ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Stevens, D. A., Ichinomiya, M., Koshi, Y., Horiuchi, H. 2006; 50 (9): 3160-3161

    Abstract

    Concentrations above the MIC of caspofungin allow growth of some Candida isolates. A strain demonstrating paradoxical growth was grown in the presence and absence of caspofungin, and the cell wall content was analyzed. Beta-1,3-glucan declined 81% in the presence of caspofungin, as expected. Beta-1,6-glucan declined 73%. Chitin increased 898%, demonstrating a mechanism for paradoxical growth-a rapid shift in the key polymer.

    View details for DOI 10.1128/AAC.00563-06

    View details for Web of Science ID 000240297000039

    View details for PubMedID 16940118

  • IL-12 induction of resistance to pulmonary blastomycosis CYTOKINE Brummer, E., Vinoda, V., Stevens, D. A. 2006; 35 (5-6): 221-228

    Abstract

    Why severity varies in blastomycosis outbreaks remains unresolved. In experimental pulmonary blastomycosis, susceptibility varied in mouse strains. In susceptible BALB/c the response is Th-2, in immunized, resistance is associated with Th-1. Can susceptibility be redirected by IL-12? Methods, results: BALB/c bronchoalveolar and peritoneal macrophages (PM) were shown deficient in IL-12 production in response to IFN-gamma+LPS. High dose IL-12 (1 microg, subcutaneously) treatment of BALB/c infected intranasally with Blastomyces resulted in enhanced survival (P<0.008). Since IL-12 was poorly tolerated, a new protocol for infected mice, IL-12 0.1 or 0.3 microg, every other day, resulted in minimal toxicity; almost all treated mice survived (P<0.002 vs. controls). When lungs of surviving mice were cultured, the 0.1 microg regimen resulted in fewer (P<0.02) cfu. For weeks after treatment, in vitro IFN-gamma treatment enabled PM Blastomyces killing. After infection spleen cells from IL-12 treated mice produced 4-fold more IFN-gamma and 3-fold less IL-10 in response to Blastomyces. IL-10 abrogated activation of macrophages by IFN-gamma for enhanced Blastomyces killing. Conclusions: A proper IL-12 treatment protocol induces resistance (survival and decreased growth in lungs), low toxicity, macrophage responsiveness to IFN-gamma for killing Blastomyces, up-regulation of IFN-gamma and down-regulation of IL-10 production.

    View details for DOI 10.1016/j.cyto.2006.08.004

    View details for Web of Science ID 000243154800001

    View details for PubMedID 17067810

  • Effect of lung surfactant collectins on bronchoalveolar macrophage interaction with Blastomyces dermatitidis: Inhibition of tumor necrosis factor alpha production by surfactant protein D INFECTION AND IMMUNITY Lekkala, M., LeVine, A. M., Linke, M. J., Crouch, E. C., Linders, B., Brummer, E., Stevens, D. A. 2006; 74 (8): 4549-4556

    Abstract

    Alveolar surfactant modulates the antimicrobial function of bronchoalveolar macrophages (BAM). Little is known about the effect of surfactant-associated proteins in bronchoalveolar lavage fluid (BALF) on the interaction of BAM and Blastomyces dermatitidis. We investigated BALF enhancement or inhibition of TNF-alpha production by BAM stimulated by B. dermatitidis. BAM from CD-1 mice were stimulated with B. dermatitidis without or with normal BALF, surfactant protein A-deficient (SP-A-/-) or surfactant protein D-deficient (SP-D-/-) BALF, or a mixture of SP-A-/- and SP-D-/- BALF. An enzyme-linked immunosorbent assay was used to measure tumor necrosis factor alpha (TNF-alpha) in culture supernatants. BALFs were standardized in protein concentration. BAM plus B. dermatitidis (BAM-B. dermatitidis) TNF-alpha production was inhibited > or = 47% by BALF or SP-A-/- BALF (at 290 or 580 microg of protein/ml, P < 0.05 to 0.01); in contrast, SP-D-/- BALF did not significantly inhibit TNF-alpha production. If SP-A-/- BALF was mixed in equal amounts with SP-D-/- BALF, TNF-alpha production by BAM-B. dermatitidis was inhibited (P < 0.01). Finally, pure SP-D added to SP-D-/- BALF inhibited TNF-alpha production by BAM-B. dermatitidis (P < 0.01). B. dermatitidis incubated with BALF and washed, plus BAM, stimulated 63% less production of TNF-alpha than did unwashed B. dermatitidis (P < 0.05). SP-D was detected by anti-SP-D antibody on BALF-treated unwashed B. dermatitidis in an immunofluorescence assay (IFA). The BALF depleted by a coating of B. dermatitidis lost the ability to inhibit TNF-alpha production (P < 0.05). 1,3-beta-Glucan was a good stimulator of BAM for TNF-alpha production and was detected on B. dermatitidis by IFA. beta-Glucan incubated with BALF inhibited the binding of SP-D in BALF to B. dermatitidis as demonstrated by IFA. Our data suggest that SP-D in BALF binds beta-glucan on B. dermatitidis, blocking BAM access to beta-glucan, thereby inhibiting TNF-alpha production. Thus, whereas BALF constituents commonly mediate antimicrobial activity, B. dermatitidis may utilize BALF constituents, such as SP-D, to blunt the host defensive reaction; this effect could reduce inflammation and tissue destruction but could also promote disease.

    View details for DOI 10.1128/IAI.00243-06

    View details for Web of Science ID 000239381400018

    View details for PubMedID 16861641

  • Coccidioidal meningitis CLINICAL INFECTIOUS DISEASES Stevens, D. A. 2006; 43 (3): 385-385

    View details for Web of Science ID 000238628300021

    View details for PubMedID 16804858

  • Animal models testing monotherapy versus combination antifungal therapy: lessons learned and future directions CURRENT OPINION IN INFECTIOUS DISEASES Clemons, K. V., Stevens, D. A. 2006; 19 (4): 360-364

    Abstract

    The continued rise in serious fungal infections and rises in therapy failure dictate that more efficacious therapies be developed. Combination therapy using available drugs is an attractive choice, yet primarily only anecdotal clinical data are available. We review here data from animal models as an indicator of future potential.The primary data are from murine studies and we will briefly review chemotherapeutic combination studies, some showing benefit over monotherapy and some showing no benefit over monotherapy. In addition, we will address the potential of immunotherapy in combination with conventional therapy.The data derived from animal model studies of antifungal drug efficacy have proven to be predictive of clinical utility. Studies on combination therapy will prove useful to the clinician in evaluating courses of treatment, especially where clinical-trial data are not available or probable in the future.

    View details for Web of Science ID 000239417200008

    View details for PubMedID 16804384

  • Development of an orogastrointestinal mucosal model of candidiasis with dissemination to visceral organs ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Clemons, K. V., Gonzalez, G. M., Singh, G., Imai, J., Espiritu, M., Parmar, R., Stevens, D. A. 2006; 50 (8): 2650-2657

    Abstract

    Studies were done to develop a murine model that mimics the pattern of mucosal candidiasis followed by disseminated disease seen in patients given cytotoxic chemotherapy. Developmental studies showed that suppression of mice with 5-fluorouracil beginning 3 days prior to infection and given every 7 days thereafter necessitated antibacterial treatment but resulted in a reproducible model. Candida albicans given in the drinking water resulted in oral infection by day 3 that significantly increased from days 10 to 15 and mucosal infection with 4 to 7 log(10) Candida CFU in the esophagus, stomach, small intestine, and cecum. Dissemination to livers occurred and was 100% on days 5 to 15; fewer animals had kidney infection. The median kidney or liver CFU were 2 or 3 log(10) CFU, respectively, on day 15; despite this, mortality was low through 21 days of infection. As a demonstration of the utility of the model to test antifungal activity, daily treatment with 10 or 50 mg/kg itraconazole significantly reduced dissemination to the liver and kidneys and reduced tongue CFU compared to controls. Overall, these studies indicate that a nonlethal model of oral and gastrointestinal mucosal candidiasis with dissemination can be established in mice. Drug efficacy in treating localized infection and in preventing or treating disseminated infection can be studied.

    View details for DOI 10.1128/AAC.00530-06

    View details for Web of Science ID 000239640400008

    View details for PubMedID 16870754

  • Efficacy of Abelcet alone, or in combination therapy, against experimental central nervous system aspergillosis JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY Clemons, K. V., Parmar, R., Martinez, M., Stevens, D. A. 2006; 58 (2): 466-469

    Abstract

    CNS aspergillosis is the most frequent and devastating manifestation of dissemination and mortality is high.Cyclophosphamide-suppressed CD-1 mice were infected intracerebrally with conidia of Aspergillus fumigatus and treated for 10 days with suboptimal doses of Abelcet (4 mg/kg) plus micafungin (1 mg/kg), caspofungin (1 mg/kg), itraconazole (100 mg/kg) or voriconazole (40 mg/kg) and compared with monotherapy. Other groups included conventional amphotericin B (1 mg/kg), Abelcet at 10 or 12 mg/kg or 5% dextrose water (diluent control).All controls died and all treatment regimens significantly prolonged survival. No monotherapy regimen was superior to another. All dosages of Abelcet and conventional amphotericin B tested were equivalent. Significant enhancement of survival over the respective monotherapies was found only with the combination of Abelcet and voriconazole. Other combinations were not better than Abelcet alone. Recovery of cfu from the brains and kidneys of survivors showed that no regimen was curative. Abelcet and voriconazole showed significantly enhanced efficacy in reducing brain infection. Other combinations showed lower cfu, but no significant enhancement over either drug alone. Dose-escalation of Abelcet alone did not increase reduction of cfu. Recovery from the kidneys showed non-significant reduction of cfu by combinations compared with monotherapies.Each of the drugs tested had significant efficacy against CNS aspergillosis and Abelcet in combination with voriconazole had enhanced efficacy. Additional studies are warranted.

    View details for DOI 10.1093/jac/dkl236

    View details for Web of Science ID 000239840700039

    View details for PubMedID 16760192

  • Who let the dogs out? Infection control did: Utility of dogs in health care settings and infection control aspects AMERICAN JOURNAL OF INFECTION CONTROL DiSalvo, H., Haiduven, D., Johnson, N., Reyes, V. V., Hench, C. P., Shaw, R., Stevens, D. A. 2006; 34 (5): 301-307

    Abstract

    Research has substantiated that animals improve human health, both psychologically and physiologically. Therefore, healthcare facilities have begun to implement programs, such as the "Furry Friends Foundation," that bring animals into the facility to improve the quality of life of patients. When implementing these programs, consideration must be given to potential adverse events such as phobias, allergies, and particularly the possibility of zoonotic disease transmission. Santa Clara Valley Medical Centre (SCVMC), a 600-bed county teaching hospital with specialized units (e.g., for burns, rehabilitation, and pediatric care), has implemented programs that incorporate animals into the healthcare setting. This facility allows three categories of dogs to interact with their patients: service dogs, therapy dogs, and pet visitation dogs by the "Furry Friends Foundation." A blurring of the roles of the three categories of dogs occurred when these programs were put into place at SCVMC. The American with Disabilities Act (ADA) states that service animals cannot be prohibited from any area. For example, a "no pet allowed" policy could not apply to these animals. Proof of a person's disability or proof of the service animal's health or training cannot be required. The purpose of this project was to maintain these programs by clarifying the policies regarding animals, specifically dogs, in the healthcare setting. This had to take place to provide a safe and enjoyable environment for the patients and the staff. A comprehensive table was developed to delineate the three categories of dogs and the corresponding policies. Therapy dogs and the visitation animals are more restricted than service dogs. Both therapy dogs and visitation dogs require identification and certification of health and are excluded from certain areas of the facility, including intensive care units and isolation rooms. By complying with the current policies and regulations, the risks from these programs can be minimized. Staff should be educated on the proper terminology and procedures to prevent a blurring of the categories and roles of these animals.

    View details for DOI 10.1016/j.ajic.2005.06.005

    View details for Web of Science ID 000238967600010

    View details for PubMedID 16765210

  • Inhibitor kappa B and nuclear factor kappa B in granulocyte-macrophage colony-stimulating factor antagonism of dexamethasone suppression of the macrophage response to Aspergillus fumigatus conidia JOURNAL OF INFECTIOUS DISEASES Choi, J. H., Brummer, E., Kang, Y. J., Jones, P. P., Stevens, D. A. 2006; 193 (7): 1023-1028

    Abstract

    The dexamethasone (DEX) immunosuppressive effect on macrophage killing activity and cytokine production in response to Aspergillus fumigatus conidia is antagonized by granulocyte-macrophage colony-stimulating factor (GM-CSF). The molecular mechanism is unknown. We postulated that this antagonism is mediated by inhibitor kappaB (I kappaB) induction by DEX and is opposed by acceleration of I kappaB degradation by GM-CSF with or without conidia stimulation, with corresponding effects on translocation and activation of nuclear factor kappa B (NF-kappaB).We studied 2 types of cells, resident peritoneal macrophages from CD-1 mice and the murine macrophage RAW264.7 cell line. Cells were unstimulated or stimulated with conidia and simultaneously treated with DEX, GM-CSF, or DEX plus GM-CSF, for 2-4 hours. I kappaB degradation and NF-kappaB activation were assessed by Western blot.Macrophages stimulated with conidia alone increased NF-kappaB translocation. DEX increased I kappaB levels in cytoplasm and blocked translocation of NF-kappaB to the nucleus in unstimulated and conidia-stimulated macrophages. Conversely, GM-CSF decreased I kappaB levels. GM-CSF reversed the effect of DEX on I kappaB levels. NF-kappaB levels were minimal in DEX-treated macrophage nuclear extracts, compared with those from GM-CSF-treated and GM-CSF plus DEX-treated macrophages.GM-CSF can reverse the DEX immunosuppressive effect by enhancing I kappaB degradation and promoting NF-kappaB translocation. This would allow macrophage production of proinflammatory cytokines, facilitating resistance to aspergillosis.

    View details for Web of Science ID 000235777000016

    View details for PubMedID 16518765

  • Assessment of the paradoxical effect of caspofungin in therapy of candidiasis ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Clemons, K. V., Espiritu, M., Parmar, R., Stevens, D. A. 2006; 50 (4): 1293-1297

    Abstract

    Paradoxical growth of some Candida albicans isolates in the presence of caspofungin (CAS) in vitro has been demonstrated previously. We sought to determine whether a similar phenomenon occurred in vivo. A systemic model of candidiasis was studied in CD-1 mice by intravenous inoculation of different isolates of C. albicans. Infected animals were treated with CAS at various dosages (0.01 to 20 mg/kg) and CFU remaining in the kidneys determined. Four clinical isolates that showed paradoxical growth in vitro and one that did not were tested. Recovery of CFU from the kidneys showed that dosages of CAS at 0.1 mg/kg and above were efficacious in the reduction of C. albicans, but were not curative. Against isolates that show paradoxical growth in vitro, CAS was efficacious, but lacked dose responsiveness above 0.5 mg/kg against three of the four. One isolate, 95-68, showed paradoxical growth in vivo with significantly higher CFU recovered from mice given CAS at 20 mg/kg than those given CAS at 5 mg/kg, but the effect was not reproducible in a subsequent experiment. When CAS was given prophylactically and therapeutically, improved efficacy and cure rate were observed. Overall, these data indicate that CAS is highly efficacious against systemic murine candidiasis and a paradoxical effect was not reproducibly demonstrated in vivo.

    View details for DOI 10.1128/AAC.50.4.1293-1297.2006

    View details for Web of Science ID 000236685700025

    View details for PubMedID 16569843

  • Temporal expression of inflammatory mediators in brain basilar artery vasculitis and cerebrospinal fluid of rabbits with coccidioidal meningitis CLINICAL AND EXPERIMENTAL IMMUNOLOGY Zucker, K. E., Kamberi, P., Sobel, R. A., Cloud, G., Meli, D. N., Clemons, K. V., Stevens, D. A., Williams, P. L., Leib, S. L. 2006; 143 (3): 458-466

    Abstract

    Strokes due to transmural vasculitis associated with coccidioidal meningitis result in significant morbidity and mortality. The immunological and inflammatory processes responsible are poorly understood. To determine the inflammatory mediators, i.e. cytokines, chemokines, iNOS, matrix metalloproteinase-9 (MMP-9), that possibly contribute to vasculitis, temporal mRNA expression in brain basilar artery samples and MMP-9 protein in the CSF of male NZW rabbits infected intracisternally with 6.5 x 10(4) arthroconidia of Coccidioides immitis were assessed. Five infected and 3 sham-injected rabbits at each time point were euthanized 4, 9, 14 and 20 days post infection. All infected rabbits had neurological abnormalities and severe vasculitis in the basilar arteries on days 9-20. In basilar arteries of infected animals versus controls, mRNAs encoding for IL-6, iNOS, IFN-gamma, IL-2, MCP-1, IL-1beta, IL-10, TNF-alpha, CCR-1, MMP-9, TGF-beta, as well as MMP-9 protein in CSF, were found to be significantly up-regulated. Thus, this study identified inflammatory mediators associated with CNS vasculitis and meningitis due to C. immitis infection. Assessment of the individual contribution of each mediator to vasculitis may offer novel approaches to the treatment of coccidioidal CNS infection. This study also provides unique methodology for immunology studies in a rabbit model.

    View details for DOI 10.1111/j.1365-2249.2006.03011.x

    View details for Web of Science ID 000235370200010

    View details for PubMedID 16487245

  • Efficacy of micafungin alone or in combination against experimental pulmonary aspergillosis MEDICAL MYCOLOGY Clemons, K. V., Stevens, D. A. 2006; 44 (1): 69-73

    Abstract

    Mortality from invasive pulmonary aspergillosis approaches 80% with few useful therapeutic options available. In these studies, we examined the efficacy of micafungin (MICA) alone or in combination with other antifungals in a model of pulmonary aspergillosis in immunosuppressed DBA/2 mice infected intranasally with conidia of Aspergillus fumigatus 10AF. In the initial study, groups of mice were given saline, or 1, 3 or 10 mg kg(-1) of MICA b.i.d., s.c. All saline controls, and 90% of untreated mice succumbed to infection. The efficacy of MICA was difficult to assess because of an apparent toxicity at 10 mg kg(-1). MICA given at 1 mg/kg significantly prolonged survival over the saline controls (P = 0.008). MICA at 3 or 10 mg kg(-1) versus the saline controls approached significance. No treatment regimen differed in efficacy. The efficacy of combination therapy was assessed, with mice given either no treatment, MICA at 1 mg/kg/dose, 0.8 mg kg(-1) of intravenous amphotericin B (AMB), 100 mg kg(-1) of oral itraconazole (ICZ), or 100 mg/kg/dose of twice-daily subcutaneous nikkomycin Z (NIK). AMB alone and MICA + AMB or MICA +NIK significantly prolonged survival (P < 0.05 - 0.02) over that of the controls. ICZ alone, ICZ+MICA and NIK alone did not significantly prolong survival. MICA alone at 1 mg/kg approached significance in prolonging survival. The combination of MICA and ICZ appeared to be potentially antagonistic. Although AMB+MICA was efficacious, no synergistic activity was noted for any of the regimens. Overall, these results indicate that MICA has moderate activity against pulmonary aspergillosis and might be useful in combination with conventional AMB.

    View details for DOI 10.1080/13693780500148350

    View details for Web of Science ID 000235382600009

    View details for PubMedID 16805095

  • Susceptibility to pulmonary blastomycosis in young compared to adult mice: immune deficiencies in young mice MEDICAL MYCOLOGY Kethineni, N., Brummer, E., Stevens, D. A. 2006; 44 (1): 51-60

    Abstract

    The immunological basis for differences in resistance to pulmonary blastomycosis between young (3 to 4-week-old) and adult (7 to 8-week-old) CD-1 mice is unknown. We assessed whether there were differences in fungicidal activity of phagocytes and Th-1 lymphocyte cytokine production. The fungicidal activity of young bronchoalveolar macrophages (BAM) (20%) against Blastomyces dermatitidis (Bd) was comparable to killing by adult BAM (25%). However, IFN-gamma enhanced the killing by adult BAM (from 30 to 69%) to a greater extent than BAM from young animals (from 20 to 30%). Killing of Bd by young peritoneal macrophages (PM) (46%) and adult PM (42%) was similar, and the enhancement of cells of both by IFN-gamma was similar. TNFalpha production by young macrophages (BAM or PM), when cocultured with Bd for 18 h, was half of TNFalpha secreted by adult macrophages. We found that polymorphonuclear neutrophils (PMN) from young mice had deficient fungicidal activity against Bd (37%) compared with adult PMN (80%). Interferon-gamma (IFN-gamma) treatment increased PMN killing of Bd by PMN of young animals from 37 to 80%. In an assessment of innate responses, we found spleen cells from young mice produced three-fold less IFN-gamma and three-fold less IL-2 than adult spleen cells in response to 1 microg/ml concanavalin A (Con A). The young spleen cells also produced more NO, which we demonstrated reduced Con A-induced proliferation. These in vitro results demonstrate several immunological deficiencies in cells from young mice and these deficiencies correlate with susceptibility. In a pilot reconstitution experiment in pulmonary blastomycosis, treatment of infected young mice with IFN-gamma (18.5 x 10(3) U, s.c.) on days 0, 1, and 2 significantly increased survival.

    View details for DOI 10.1080/13693780500220498

    View details for Web of Science ID 000235382600007

    View details for PubMedID 16805093

  • Comparative efficacies of conventional amphotericin B, liposomal amphotericin B (AmBisome), caspofungin, micafungin, and voriconazole alone and in combination against experimental murine central nervous system aspergillosis ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Clemons, K. V., Espiritu, M., Parmar, R., Stevens, D. A. 2005; 49 (12): 4867-4875

    Abstract

    Central nervous system (CNS) aspergillosis is a severe disease that responds poorly to current therapies. The current studies examined the efficacies of several antifungal agents alone or in combination with a murine model of CNS aspergillosis. Immunosuppressed mice were infected intracerebrally with Aspergillus fumigatus and treated with an amphotericin B preparation, an echinocandin, or voriconazole (VCZ) given alone or in combination. Monotherapy studies showed that micafungin (MICA), caspofungin (CAS), VCZ, conventional amphotericin B (AMB), Abelcet (ABLC) (a lipid-carried AMB formulation; Enzon Pharmaceuticals, Inc.), and AmBisome (AmBi) (liposomal AMB; Gilead Sciences, Inc.) were efficacious. However, doses of AmBi above 15 mg/kg of body weight showed reduced efficacy. Neither MICA nor CAS showed dose responsiveness at the doses tested (1, 5, or 10 mg/kg). Only the 40-mg/kg dose of VCZ was effective. AmBi and ABLC showed dose responsiveness, with 10-mg/kg doses causing a significant reduction in fungal burden; they had equivalent activities at the 10-mg/kg dose. Suboptimal dosages of AmBi in combination with MICA, CAS, or VCZ were effective in prolonging survival. However, significantly enhanced activity was demonstrated only with AmBi and VCZ in combination. AmBi in combination with MICA or CAS showed a trend toward enhanced activity, but the combination was not significantly superior to monotherapy. The use of AmBi with CAS or VCZ at optimal doses did not improve efficacy. Cure was not attained with any dosage combinations. These results indicate that AmBi in combination with VCZ may be superior for treatment of CNS aspergillosis; combinations of AmBi and MICA or CAS were not antagonistic and may have a slight benefit.

    View details for DOI 10.1128/AAC.49.12.4867-4875.2005

    View details for Web of Science ID 000233692100006

    View details for PubMedID 16304147

  • Coccidioidomycosis CLINICAL INFECTIOUS DISEASES Galgiani, J. N., Ampel, N. M., Blair, J. E., Catanzaro, A., Johnson, R. H., Stevens, D. A., Williams, P. L. 2005; 41 (9): 1217-1223

    View details for Web of Science ID 000232356300006

    View details for PubMedID 16206093

  • Immunological basis for susceptibility and resistance to pulmonary blastomycosis in mouse strains CYTOKINE Brummer, E., Kethineni, N., Stevens, D. A. 2005; 32 (1): 12-19

    Abstract

    The immunological basis for a >10-fold resistance of outbred CD-1 mice compared to inbred BALB/c mice to pulmonary blastomycosis was investigated. Bronchoalveolar macrophages (BAM) from CD-1 mice killed yeast cells of Blastomyces dermatitidis (Bd) by 25% and this increased to 59% when activated by IFN-gamma. In contrast, BAM from BALB/c mice lacked significant killing (5%) of Bd but could be activated by IFN-gamma for enhanced killing (19%). Peritoneal macrophages (PM) from CD-1 mice had significant fungicidal activity for Bd (43%) and this increased to 63% with IFN-gamma treatment. By contrast, PM from BALB/c mice did not significantly kill Bd (14%) but were activated by IFN-gamma for significant killing (24%). Fungicidal activity of peripheral blood polymorphonuclear neutrophils (PMN) from CD-1 (87%) was greater than that of BALB/c (75%) (P<0.05). Macrophage inflammatory protein-1alpha (MIP-1alpha) production by BAM from BALB/c was significantly less than that from CD-1 in response to co-culture with Bd. IFN-gamma production by CD-1 spleen cells in response to concanavalin A (Con A, 1microg/ml) was 8-fold greater than that by BALB/c spleen cells. In contrast, BAM and PM from BALB/c mice in co-culture with Bd secreted several-fold more TNFalpha than BAM or PM from CD-1 mice. IL-2 production by BALB/c spleen cells in response to Con A was 3- to 4-fold greater than that by CD-1 spleen cells. Depressed IL-2 production by Con A stimulated CD-1 spleen cells correlated with depressed proliferative responses. Resistance of CD-1 mice to pulmonary blastomycosis correlates with enhanced fungicidal activity of BAM, PM, PMN, and IFN-gamma production by Con A stimulated spleen cells, compared to BALB/c mice. Consistent with the in vitro enhancement of effector cell function by IFN-gamma, in vivo therapy with IFN-gamma significantly (P<0.0001) improved survival of BALB/c mice with pulmonary blastomycosis.

    View details for DOI 10.1016/j.cyto.2005.07.004

    View details for Web of Science ID 000232712100003

    View details for PubMedID 16183299

  • Efficacy of Abelcet and caspofungin, alone or in combination, against CNS aspergillosis in a murine model JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY Imai, J., Singh, G., Fernandez, B., Clemons, K. V., Stevens, D. A. 2005; 56 (1): 166-171

    Abstract

    Currently, few options exist to treat central nervous system (CNS) aspergillosis, which is usually fatal. We tested the efficacy of Abelcet and caspofungin, alone and in combination for treatment of this disease.Male CD-1 mice were immunosuppressed with 200 mg/kg cyclophosphamide 2 days prior to infection and every 5 days thereafter. In the first study, mice were infected intracerebrally with 2.1 x 10(6) conidia/mouse of Aspergillus fumigatus; 10 days of once daily therapy began one day later. Groups of 10 received 0.8, 4, or 8 mg/kg of Abelcet, intravenously (iv), or caspofungin, intraperitoneally, 0.8 mg/kg of conventional amphotericin B (AmB) iv, or no treatment. In a second study, mice were challenged with 6.4 x 10(6) conidia and given no treatment, 8 mg/kg of Abelcet or caspofungin, alone or in combination. On day 14, cfu were determined in survivors by plating of organ homogenates.In the first study, mice given any regimen of Abelcet or caspofungin had a survival rate > or =80% whereas untreated had 90% mortality. All drug regimens prolonged survival (P < or = 0.0008) and reduced cfu (P < or = 0.0001-0.003) recovered from the brains and kidneys compared with untreated. Abelcet showed an apparent dose-related reduction of cfu in the brains. Abelcet at 4 or 8 mg/kg were equivalent to AmB in reducing cfu from both organs (P > 0.05); AmB was superior to 0.8 mg/kg of Abelcet in the brain only (P < 0.02). Abelcet at 8 mg/kg or AmB at 0.8 mg/kg were superior to all regimens of caspofungin in reducing cfu (P < or = 0.05-0.001). In the second study, Abelcet alone significantly prolonged survival and reduced cfu in the organs versus the controls. Caspofungin did not significantly prolong survival or reduce cfu in comparison with the controls. In combination, Abelcet and caspofungin were equivalent to Abelcet alone.Abelcet proved to be efficacious, but not curative, in the treatment of CNS aspergillosis and was equivalent overall to conventional AmB. Caspofungin was not as effective against the larger inoculum, but did not enhance or interfere with the efficacy of Abelcet. Since Abelcet displayed dose-responsive efficacy, it is possible higher doses could produce superior results, yet not show toxicity.

    View details for DOI 10.1093/jac/dki178

    View details for Web of Science ID 000230724800021

    View details for PubMedID 15917284

  • Studies on itraconazole delivery and pharmacokinetics in mallard ducks (Anas platyrhynchos) JOURNAL OF VETERINARY PHARMACOLOGY AND THERAPEUTICS Tell, L. A., Craigmill, A. L., Clemons, K. V., Sun, Y., Laizure, S. C., Clifford, A., Ina, J. H., Nugent-Deal, J. P., Woods, L., Stevens, D. A. 2005; 28 (3): 267-274

    Abstract

    Avian aspergillosis is commonly treated with itraconazole (ITZ). This paper describes two studies using mallard ducks (Anas platyrhynchos). The first study evaluated in vivo release of ITZ from subcutaneously injected controlled-release gel formulations and the second study compared pharmacokinetic parameters for two ITZ oral suspensions. ITZ-A suspension was prepared by mixing contents of commercially available capsules with hydrochloric acid and orange juice. ITZ-B suspension was prepared by dispersing the complex of the drug with hydroxypropyl-beta-cyclodextrin in water. Concentrations of ITZ and its active metabolite, hydroxyitraconazole (OH-ITZ), in plasma and tissue samples were measured using high-performance liquid chromatography. In the second study, drug concentrations in plasma samples were also analyzed using a bioassay. After administration of two ITZ controlled-release formulations, plasma and tissue concentrations of ITZ and OH-ITZ were either very low (< or = 52 ng/mL) or undetectable. Exceptions included skin, subcutaneous fat, and muscle adjacent to the injection site. The drug from ITZ-A and ITZ-B suspensions was absorbed after oral administration. ITZ pharmacokinetic parameters for both suspensions in mallard ducks were similar and the bioassay successfully measured ITZ equivalents in plasma samples from ducks.

    View details for Web of Science ID 000229680600005

    View details for PubMedID 15953200

  • Interaction between conidia, lung macrophages, immunosuppressants, proinflammatory cytokines and transcriptional regulation MEDICAL MYCOLOGY Brummer, E., Choi, J. H., Stevens, D. A. 2005; 43: S177-S179

    Abstract

    The immunosuppressive effect of dexamethasone (DEX) on macrophage killing activity and cytokine production in response to Aspergillus fumigatus conidia is antagonized by granulocyte-macrophage colony-stimulating factor (GM-CSF). However, the intersection of signaling pathways and the molecular mechanism of this antagonism remain to be defined. We postulated that DEX inhibition of NF-kappaB was opposed by induction of IkappaB kinases (IKK) by GM-CSF + conidia stimulation, degradation of IkappaB, and release of nuclear factor kappa B (NF-kappaB). This hypothesis was tested using resident peritoneal macrophages from CD-1 mice and the murine macrophage RAW 264.7 cell line. Macrophages were unstimulated or stimulated with A. fumigatus conidia and simultaneously treated with DEX, GM-CSF or DEX + GM-CSF for 2 4 hours. IkappaB degradation in cytoplasmic extracts and translocation of NF-kappaB in nuclear extracts was measured by Western blot analysis. This showed GM-CSF reverses the immunosuppressive effect of DEX by enhancing the degradation of IkappaB and promoting the translocation of NF-kappaB to the nucleus. This would allow the production of proinflammatory cytokines by macrophages, facilitating resistance to A. fumigatus.

    View details for DOI 10.1080/13693780500051497

    View details for Web of Science ID 000230896300029

    View details for PubMedID 16110809

  • The contribution of animal models of aspergillosis to understanding pathogenesis, therapy and virulence MEDICAL MYCOLOGY Clemons, K. V., Stevens, D. A. 2005; 43: S101-S110

    Abstract

    Animal models of aspergillosis have been used extensively to study various aspects of pathogenesis, innate and acquired host-response, disease transmission and therapy. Several different animal models of aspergillosis have been developed. Because aspergillosis is an important pulmonary disease in birds, avian models have been used successfully to study preventative vaccines. Studies done to emulate human disease have relied on models using common laboratory animal species. Guinea pig models have primarily been used in therapy studies of invasive pulmonary aspergillosis (IPA). Rabbits have been used to study IPA and systemic disease, as well as fungal keratitis. Rodent, particularly mouse, models of aspergillosis predominate as the choice for most investigators. The availability of genetically defined strains of mice, immunological reagents, cost and ease of handling are factors. Both normal and immunosuppressed animals are used routinely. These models have been used to determine efficacy of experimental therapeutics, comparative virulence of different isolates of Aspergillus, genes involved in virulence, and susceptibility to infection with Aspergillus. Mice with genetic immunological deficiency and cytokine gene-specific knockout mice facilitate studies of the roles cells, and cytokines and chemokines, play in host-resistance to Aspergillus. Overall, these models have been critical to the advancement of therapy, and our current understanding of pathogenesis and host-resistance.

    View details for DOI 10.1080/13693780500051919

    View details for Web of Science ID 000230896300018

    View details for PubMedID 16110800

  • Efficacy of caspofungin against central nervous system Aspergillus fumigatus infection in mice determined by TaqMan PCR and CFU methods ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Singh, G., Imai, J., Clemons, K. V., Stevens, D. A. 2005; 49 (4): 1369-1376

    Abstract

    We have reported previously that prolonged caspofungin (CAS) dosing enhances survival in a murine model of central nervous system aspergillosis. In this study we determined by quantitative PCR (qPCR) and CFU enumeration whether CAS could reduce fungal burdens, prior to the deaths of untreated animals, and also assessed progressive infection in untreated mice. Mice were infected intracranially and treated for 4 days with CAS (1, 5, or 10 mg/kg of body weight/day) or amphotericin B (AMB) (3 mg/kg/day) starting 1 day postinfection. Fungal burdens in brains and kidneys of untreated controls were determined on days 1, 3, and 5 to assess progressive infection; burdens in treated animals were determined on day 5. qPCR showed higher burdens than CFU enumeration in all comparisons. In untreated animals, qPCR showed transiently increased burdens in brains, while CFU enumeration showed a decrease. qPCR showed increased burdens in kidneys, but CFU enumeration did not. Neither method indicated drug efficacy in the brain. Both methods showed AMB efficacy in the kidneys, and qPCR demonstrated CAS efficacy at all doses. Spearman correlations of qPCR and CFU determination results showed a significant correlation for most untreated groups; results correlated well for kidneys (P < or = 0.03) but not for brains in treated mice. Regression analyses of qPCR and CFU groups indicated different slopes for progressive infection in untreated animals but the same slopes for CAS dose-response efficacy. qPCR appeared to better reflect the progression of untreated infection. The lack of demonstration of efficacy in the brain suggests that longer dosing is necessary to cause burden reduction. These results also suggest that, when there is drug efficacy in a therapeutic study, either method appears to be useful for determining Aspergillus fumigatus burdens.

    View details for DOI 10.1128/AAC.49.4.1369-1376.2005

    View details for Web of Science ID 000228082500018

    View details for PubMedID 15793114

  • Studies of the paradoxical effect of caspofungin at high drug concentrations DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE Stevens, D. A., White, T. C., Perlin, D. S., Selitrennikoff, C. P. 2005; 51 (3): 173-178

    Abstract

    Turbid growth of some Candida albicans isolates occurs, paradoxically, in some high concentrations of caspofungin, above the minimum inhibitory concentration. We show that the resistant phenotype is first detectable after 24 h of drug exposure. Although other studies have suggested an association between some azole resistance mechanisms and caspofungin resistance, our studies with isolates susceptible and resistant to azoles (the latter including groups with defined resistance mechanisms and derived mutants) suggest a weak association at most with a paradoxical effect. The paradoxical growth is not related to mutations in resistance-associated regions of the (1,3)-beta-glucan synthase complex and is not related to an up-regulation of (1,3)-beta-glucan synthase activity in the presence of drug. Subculture of a minority of tubes above the minimum fungicidal concentration yielded a few viable cells, suggesting random distribution, in some strains, of a few cells with propensity to grow in the presence of drug. We postulate high drug concentrations derepress or activate an as-yet undefined resistance mechanism(s).

    View details for DOI 10.1016/j.diagmicrobio.2004.10.006

    View details for Web of Science ID 000228091200003

    View details for PubMedID 15766602

  • Efficacy of posaconazole in a murine model of central nervous system aspergillosis ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Imai, J. K., Singh, G., Clemons, K. V., Stevens, D. A. 2004; 48 (10): 4063-4066

    Abstract

    Human central nervous system (CNS) aspergillosis has >90% mortality. We compared posaconazole with other antifungals for efficacy against murine CNS aspergillosis. All tested regimens of posaconazole were equivalent to those of amphotericin B and superior in prolonging survival and reducing CFU to those of itraconazole and caspofungin and to vehicle controls. No antifungal regimen effected cure. No toxicity was noted. Overall, posaconazole shows potential for treating CNS aspergillosis.

    View details for DOI 10.1128/AAC.48.10.4063-4066.2004

    View details for Web of Science ID 000224217000068

    View details for PubMedID 15388482

  • Paradoxical effect of caspofungin: Reduced activity against Candida albicans at high drug concentrations ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Stevens, D. A., Espiritu, M., Parmar, R. 2004; 48 (9): 3407-3411

    Abstract

    Resistance problems with caspofungin, an echinocandin inhibitor of fungal cell wall glucan synthesis, have been rare. We noted paradoxical turbid growth of Candida albicans isolates in broth in some high (supra-MIC) concentrations. Among isolates submitted for susceptibility testing and screened at drug concentrations up to 12.5 microg/ml, the frequency was 16%. Analysis of the turbid growth indicated slowing of growth in the presence of drug but with numbers of CFU up to 72% those of drug-free controls. Clearing of growth again by the highest drug concentrations produced a quadriphasic pattern in a tube dilution series. Cells growing at high drug concentrations were not resistant on retesting but showed the paradoxical effect of the parent. Among a selected series of isolates tested at concentrations up to 50 microg/ml, an additional 53% showed a "mini-paradoxical effect": no turbid growth but incomplete killing at high concentrations (supra-minimum fungicidal concentration). These effects were reproducible; medium dependent in extent; noted in macro- and microdilution, in the presence or absence of serum, and on agar containing drug (but not when drug concentrations were not constant, as in agar diffusion); not seen with other echinocandins and less commonly in other Candida species; and not due to destruction of drug in tubes showing the effect. Cooperative enhancement of inhibition by a second drug could eradicate the effect. We postulate that high drug concentrations derepress or activate resistance mechanisms. The abilities of subpopulations to survive at high drug concentrations could have in vivo consequences.

    View details for DOI 10.1128/AAC.48.9.3407-3411.2004

    View details for Web of Science ID 000223625800029

    View details for PubMedID 15328104

  • Genetic susceptibility of mice to Candida albicans vaginitis correlates with host estrogen sensitivity INFECTION AND IMMUNITY Clemons, K. V., Spearow, J. L., Parmar, R., Espiritu, M., Stevens, D. A. 2004; 72 (8): 4878-4880

    Abstract

    We compared susceptibility to Candida vaginitis in derived murine substrains differing in sensitivity to estrogen (CD-1 and CD10, resistant; CD3 and C57BL/6 responsive), and in F1 crosses. The order of decreasing resistance was CD-1 > or = CD10 > or = CD10 x CD3F1 > CD10 x B6F1 > CD3 > C57BL/6 and correlated with estrogen responsiveness in endocrine disruptor assays. Resistance to Candida vaginitis appears additive in CD10 x B6F1 animals and dominant in CD10 x CD3F1 animals.

    View details for DOI 10.1128/IAI.72.8.4878-4880.2004

    View details for Web of Science ID 000222932600066

    View details for PubMedID 15271952

  • Genotypic differences of Candida albicans and C-dubliniensis isolates related to ethnic/racial differences within the same geographic area MYCOPATHOLOGIA McCullough, M. J., Jorge, J. J., Lejbkowicz, F., Lefler, E., Nassar, F., Clemons, K. V., Stevens, D. A. 2004; 158 (1): 39-41

    Abstract

    Candida albicans and C. dubliniensis genotype differences among Israeli ethnic groups were assessed. Isolates from Jews (51), Arabs (35) and Druze (25) were genotyped. The distributions among ethnic groups were not different, however they differed (p = 0.002) from global populations. Therefore, C. albicans and C. dubliniensis genotype distribution differences in Israel are related to changes in all ethnic groups.

    View details for Web of Science ID 000223373000006

    View details for PubMedID 15487318

  • Vaccinate against aspergillosis! A call to arms of the immune system CLINICAL INFECTIOUS DISEASES Stevens, D. A. 2004; 38 (8): 1131-1136

    Abstract

    Invasive aspergillosis is a devastating and increasingly common disease, seen almost exclusively in immunosuppressed patients. Immunizing an immunocompromised host would seem to be a formidable task; however, virulence factors and immunogens of the pathogen have now been identified and could be targeted, mapping of the genome sequence of the pathogen will soon be completed, and the protective host immune responses and cytokine networking are better understood. These facts, together with recent advances in vaccine science, make consideration of such an approach now possible. Some populations that are at risk for aspergillosis might be likely candidates for receiving the first vaccinations against aspergillosis, or vaccination of a stem cell donor might be considered in some circumstances. Successful immunizations have been demonstrated in turkeys and mice.

    View details for Web of Science ID 000220735200015

    View details for PubMedID 15095219

  • Cytokine and inducible nitric oxide synthase mRNA expression during experimental murine cryptococcal meningoencephalitis INFECTION AND IMMUNITY Maffei, C. M., Mirels, L. F., Sobel, R. A., Clemons, K. V., Stevens, D. A. 2004; 72 (4): 2338-2349

    Abstract

    The immune events that take place in the central nervous system (CNS) during cryptococcal infection are incompletely understood. We used competitive reverse transcription-PCR to delineate the time course of the local expression of mRNAs encoding a variety of cytokines and inducible nitric oxide synthase (iNOS) during progressive murine cryptococcal meningoencephalitis and assessed the CNS inflammatory response using immunohistochemistry. Interleukin 18 (IL-18), transforming growth factor beta1, and IL-12p(40) mRNAs were constitutively expressed in the brains of infected and uninfected mice; IL-2 mRNA was not detected at any time. Increased levels of transcripts corresponding to IL-1 alpha, tumor necrosis factor alpha (TNF-alpha), and iNOS were detected as early as day 1 postinfection, with TNF-alpha rising by approximately 30-fold and iNOS increasing by approximately 5-fold by day 7. Each remained at these levels thereafter. IL-4, IL-6, and gamma interferon transcripts were detected on day 5, and IL-1 beta and IL-10 transcripts were detected beginning on day 7. Once detected, each remained at a relatively constant level through 28 days of infection. This cytokine profile does not suggest a polarized Th1 or Th2 response. Immunohistochemistry did not reveal inflammatory infiltrates before day 7, despite the presence of cryptococci. Intraparenchymal abscesses with inflammatory cells in their peripheries were found beginning on day 10. The infiltrates were comprised primarily of cells expressing CD4, CD8, or CD11b; low numbers of cells expressing CD45R/B220 were also present. The persistence of Cryptococcus observed in the CNS may result from an ineffective immune response, perhaps owing to an insufficient anticryptococcal effector function of endogenous glial cells resulting from competing pro- and anti-inflammatory cytokines. These data detail the immune response in the brain and could be important for the future design of specific immunomodulatory therapies for this important opportunistic infection.

    View details for DOI 10.1128/IAI.72.4.2338-2349.2004

    View details for Web of Science ID 000220481600057

    View details for PubMedID 15039359

  • Combined action of micafungin, a new echinocandin, and human phagocytes for antifungal activity against Aspergillus fumigatus MICROBES AND INFECTION Choi, J. H., Brummer, E., Stevens, D. A. 2004; 6 (4): 383-389

    Abstract

    Micafungin, a new echinocandin, inhibits fungal cell wall beta-glucan synthesis. We postulated micafungin and host phagocytic cells could act together in damaging fungi. Using the metabolic XTT assay, micafungin alone (0.01 and 0.10 microg/ml) inhibited Aspergillus fumigatus germlings by 48% and 61%, respectively. Polymorphonuclear neutrophils (PMNs) inhibited germlings by 53%. Micafungin at 0.01 or 0.10 microg/ml and PMNs resulted in additive inhibition, 82% and 99%, respectively. Monocyte-derived macrophage (MDM) monolayers inhibited germling growth by 66%; micafungin (0.01 or 0.10 microg/ml) alone inhibited by 32% and 42%, respectively. MDMs and micafungin (0.01 or 0.10 microg/ml) caused an additive inhibition of growth, 85% and 95%, respectively. Hyphae were generated by incubation of conidia for 24 h with or without micafungin. PMNs alone, added to hyphae, inhibited growth by 19% in the subsequent 20 h. Hyphae generated in the presence of micafungin (0.10 microg/ml) and subsequently cultured with micafungin for 24 h inhibited growth by 64%. PMNs plus micafungin resulted in 82% inhibition. Monocytes alone inhibited hyphal growth by only 5%. Hyphae produced in the presence of micafungin (0.01 microg/ml) and incubated again with micafungin for 24 h inhibited growth by 47%; combination with monocytes resulted in 62% inhibition. These data indicate that micafungin inhibits growth of tissue forms of A. fumigatus, and phagocytes and micafungin together have an additive effect. These findings support the thesis that the greater efficacy of micafungin in vivo compared with in vitro could be due to combined effect of phagocytic cells and micafungin.

    View details for DOI 10.1016/j.micinf.2003.12.010

    View details for Web of Science ID 000220770600006

    View details for PubMedID 15050966

  • Comparative efficacies of four amphotericin B formulations - Fungizone, amphotec (Amphocil), AmBisome, and Abelcet - against systemic murine aspergillosis ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Clemons, K. V., Stevens, D. A. 2004; 48 (3): 1047-1050

    Abstract

    We compared various amphotericin B formulations (no treatment or 0.8 mg of Fungizone [conventional deoxycholate amphotericin B] per kg of body weight, or 0.8, 4, or 8 mg of Amphocil, AmBisome, or Abelcet per kg of body weight) for treatment of systemic murine aspergillosis. In two studies, all formulations prolonged survival, with the results for AmBisome nearly equivalent to those for Fungizone; Amphocil and Abelcet were less effective or equivalent depending on the severity of infection. No survivors were cured in both kidneys and brain, but each formulation showed efficacy, especially in the kidneys. Although higher doses could be given, no lipid-based formulation showed consistent superiority over Fungizone or over each other.

    View details for DOI 10.1128/AAC.48.3.1047-1050.2004

    View details for Web of Science ID 000189351700054

    View details for PubMedID 14982807

  • Combination and sequential antifungal therapy for invasive aspergillosis: Review of published in vitro and in vivo interactions and 6281 clinical cases from 1966 to 2001 CLINICAL INFECTIOUS DISEASES Steinbach, W. J., Stevens, D. A., Denning, D. W. 2003; 37: S188-S224

    Abstract

    The development of newer antifungal drugs is creating new potential combination therapies to combat the dismal mortality rate associated with invasive aspergillosis (IA). The efficacy of combination therapy for IA has not been established; sparse data on combination or sequential antifungal therapy depict interactions ranging from synergy to antagonism. We reviewed data from all published in vitro studies, animal model studies, and clinical reports and recent abstracts on combination and sequential antifungal therapy for IA from 1966-2001. Among cases of IA during 1966-2001, 249 were treated with 23 different antifungal combinations. Amphotericin B plus 5-fluorocytosine was the most commonly used (49% of cases), followed by amphotericin B plus itraconazole (16%) or plus rifampin (11%). Combination therapy resulted in improvement in 63% of patients, generally with amphotericin B plus 5-fluorocytosine or rifampin and indifference with amphotericin B plus itraconazole. In 27 in vitro reports, we found synergy (in 36% of reports), additivity (in 24%), indifference (in 28%), and antagonism (in 11%). Amphotericin B plus 5-fluorocytosine and amphotericin B plus rifampin showed generally positive interactions and amphotericin B plus itraconazole showed results that were largely indifferent. Eighteen animal model reports demonstrated synergy (in 14% of reports), additivity (in 20%), indifference (in 51%), and antagonism (in 14%). In general, amphotericin B plus 5-fluorocytosine, amphotericin B plus rifampin, and amphotericin B plus itraconazole showed indifferent results, whereas amphotericin B plus micafungin showed positive interactions. Thirty-four cases treated during 1990-2001 with sequential therapy, excluding amphotericin B followed by itraconazole, showed improvement in 68% of cases. Improvement was noted with amphotericin B or itraconazole followed by voriconazole but not with itraconazole followed by amphotericin B.

    View details for Web of Science ID 000186262900003

    View details for PubMedID 12975752

  • Invasive aspergillosis in the setting of cardiac transplantation CLINICAL INFECTIOUS DISEASES Montoya, J. G., Chaparro, S. V., Celis, D., Cortes, J. A., Leung, A. N., Robbins, R. C., Stevens, D. A. 2003; 37: S281-S292

    Abstract

    Among patients undergoing heart transplantation, Aspergillus is the opportunistic pathogen with the highest attributable mortality. The median time of onset from transplantation for invasive pulmonary aspergillosis (IPA) was 46 days, but the median time to first positive culture result was 104 days among patients with Aspergillus colonization but no invasive disease. Most patients with IPA presented with fever and cough within the first 90 days of transplantation and with single or multiple pulmonary nodules. None of the heart transplant recipients with either IPA or invasive extrapulmonary aspergillosis (IEPA) had associated neutropenia. Human leukocyte antigen A1 locus was found significantly more frequently among patients colonized with Aspergillus than among patients with IPA (P<.006) or IEPA (P<.001). Even in the absence of neutropenia, IPA should be suspected for heart transplant recipients who have fever and respiratory symptoms within the first 3 months of transplantation, have a positive result of culture of respiratory secretions, and have abnormal radiological findings (particularly nodules).

    View details for Web of Science ID 000186262900006

    View details for PubMedID 12975755

  • Review of newer antifungal and immunomodulatory strategies for invasive aspergillosis CLINICAL INFECTIOUS DISEASES Steinbach, W. J., Stevens, D. A. 2003; 37: S157-S187

    Abstract

    The incidence of invasive aspergillosis is markedly increasing, and mortality remains dismal. Previously there were only 2 antifungals with activity against Aspergillus, but over the last few years there has been an explosion of newer agents and reformulations of older antifungals. Exploration has also begun with immunotherapy, with use of cytokines and granulocyte transfusions alone or in combination with antifungal therapy. This review will detail the available in vitro, in vivo, and clinical experience with the newer antifungal and immunomodulatory therapies in development for treatment of invasive aspergillosis.

    View details for Web of Science ID 000186262900002

    View details for PubMedID 12975751

  • Advances against aspergillosis CLINICAL INFECTIOUS DISEASES Steinbach, W. J., Stevens, D. A., Denning, D. W., Moss, R. B. 2003; 37: S155-S156

    View details for Web of Science ID 000186262900001

    View details for PubMedID 12975750

  • Allergic bronchopulmonary aspergillosis in cystic fibrosis - State of the art: Cystic Fibrosis Foundation Consensus Conference CLINICAL INFECTIOUS DISEASES Stevens, D. A., Moss, R. B., Kurup, V. P., Knutsen, A. P., Greenberger, P., Judson, M. A., Denning, D. W., Crameri, R., Brody, A. S., Light, M., Skov, M., Maish, W., Mastella, G. 2003; 37: S225-S264

    Abstract

    Because of the difficulties of recognizing allergic bronchopulmonary aspergillosis (ABPA) in the context of cystic fibrosis (because of overlapping clinical, radiographic, microbiologic, and immunologic features), advances in our understanding of the pathogenesis of allergic aspergillosis, new possibilities in therapy, and the need for agreed-upon definitions, an international consensus conference was convened. Areas addressed included fungal biology, immunopathogenesis, insights from animal models, diagnostic criteria, epidemiology, the use of new immunologic and genetic techniques in diagnosis, imaging modalities, pharmacology, and treatment approaches. Evidence from the existing literature was graded, and the consensus views were synthesized into this document and recirculated for affirmation. Virulence factors in Aspergillus that could aggravate these diseases, and particularly immunogenetic factors that could predispose persons to ABPA, were identified. New information has come from transgenic animals and recombinant fungal and host molecules. Diagnostic criteria that could provide a framework for monitoring were adopted, and helpful imaging features were identified. New possibilities in therapy produced plans for managing diverse clinical presentations.

    View details for Web of Science ID 000186262900004

    View details for PubMedID 12975753

  • Management of varicella-vaccinated patients and employees exposed to varicella in the healthcare setting INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY Haiduven, D. J., Hench, C. R., Simpkins, S. M., Scott, K. E., Stevens, D. A. 2003; 24 (7): 538-543

    View details for Web of Science ID 000184264100014

    View details for PubMedID 12887244

  • Caspofungin CLINICAL INFECTIOUS DISEASES Deresinski, S. C., Stevens, D. A. 2003; 36 (11): 1445-1457

    Abstract

    Caspofungin, the first inhibitor of fungal beta-1,3 glucan synthesis to receive approval by the United States Food and Drug Administration, is effective for the treatment of mucosal and invasive candidiasis and invasive aspergillosis. It is also active in vitro and in animal models against a number of other filamentous and dimorphic endemic fungi and in animal models of Pneumocystis carinii infection. In vitro studies and some animal studies almost always indicate an absence of antagonism when caspofungin is combined with azole or polyene antifungal agents. Caspofungin has an excellent safety profile. Caspofungin may prove to be useful in empirical therapy for suspected invasive fungal infections. Additional clinical trial data that expand our knowledge of the usefulness of caspofungin for these and other mycoses, including its administration in combination with other antifungal agents, is anticipated. Caspofungin is an important addition to the antifungal pharmacopoeia.

    View details for Web of Science ID 000183126500015

    View details for PubMedID 12766841

  • Genetic susceptibility to vaginal candidiasis MEDICAL MYCOLOGY Calderon, L., WILLIAMS, R., Martinez, M., Clemons, K. V., Stevens, D. A. 2003; 41 (2): 143-147

    Abstract

    To enable future studies on host resistance factors and therapy, inbred and outbred mouse strains were tested for susceptibility to vaginal candidiasis. Groups of mice were given 0.5 mg estradiol 3 days before and 4 days after intravaginal challenge with a suspension of Candida albicans. On day 1 after challenge, a swab was used to quantitate infection in all groups and to assure equivalent infection levels. On day 6, this was repeated and the experiment was terminated. BALB/c, the reference strain in repeated experiments, was susceptible, showing persistent infection with levels of cfu at day 6 falling within a range between a twofold decrease and a fourfold increase in relation to day 1 levels. CD-1 outbred mice were markedly resistant, with day 6 cfu levels showing a 74- to 87-fold decrease with respect to day 1 levels, whereas other outbred strains (CF-1, SW, ICR) were susceptible. A BALB/c substrain (ByJ) was also susceptible. With exception of CBA/J, which showed modest resistance, all inbred strains were similarly susceptible, including DBA/2, AKR/J, C3H/HeN, A/J and C57BL/6. The differences between CD-1 and BALB/c mice were also seen with a second C. albicans isolate. Our results show susceptibility to vaginal candidiasis is independent of the major histocompatibility locus H2 haplotype and any effect ascribable to use of particular commercial mouse suppliers. Differences among mouse strains in susceptibility to C. albicans, as seen in previous studies involving nonvaginal challenge routes, are not reflected in this vaginal candidiasis model; in general, such resistance patterns appear specific to the route of challenge administration. The resistance seen in mouse strain CD-1 is of particular interest in that CD-1 is known to be resistant to endocrine disruption by estrogen. Our results suggest this estrogen insensitivity may have broad-ranging effects on processes other than gametogenesis, including vaginal susceptibility to candidiasis.

    View details for Web of Science ID 000226559700009

    View details for PubMedID 12964847

  • Efficacy of micafungin alone or in combination against systemic murine aspergillosis ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Luque, J. C., Clemons, K. V., Stevens, D. A. 2003; 47 (4): 1452-1455

    Abstract

    We tested the efficacy of micafungin (FK) alone or in combination with other antifungals against systemic murine aspergillosis. FK alone at 10 mg/kg of body weight/dose prolonged survival (P = 0.01) and reduced CFU in the brain and kidney. Combination therapy that used suboptimal FK with amphotericin B or itraconazole prolonged survival. Although no survivors were free of infection, no antagonism was seen. Nikkomycin Z with FK showed significantly greater potency (P < 0.01) than either alone.

    View details for DOI 10.1128/AAC.47.4.1452-1455.2003

    View details for Web of Science ID 000181842000049

    View details for PubMedID 12654692

  • Coccidioidomycosis INFECTIOUS DISEASE CLINICS OF NORTH AMERICA Chiller, T. M., Galgiani, J. N., Stevens, D. A. 2003; 17 (1): 41-?

    Abstract

    Coccidioides, a fungus, is endemic to specific parts of the Western Hemisphere. This article examines the prevalence, pathogenesis and host defense, clinical manifestations, diagnosis, and treatment of coccidioidomycosis.

    View details for Web of Science ID 000182500800004

    View details for PubMedID 12751260

  • Regulation by granulocyte-macrophage colony-stimulating factor and/or steroids given in vivo of proinflammatory cytokine and chemokine production by bronchoalveolar macrophages in response to Aspergillus conidia JOURNAL OF INFECTIOUS DISEASES Brummer, E., Kamberi, M., Stevens, D. A. 2003; 187 (4): 705-709

    Abstract

    Production of the proinflammatory cytokines interleukin (IL)-1 alpha and tumor necrosis factor (TNF)-alpha and of the chemotactic chemokine macrophage inflammatory protein (MIP)-1 alpha by bronchoalveolar macrophages (BAMs) from mice in response to Aspergillus conidia was tested after in vivo administration of saline, dexamethasone, cortisone acetate, granulocyte-macrophage colony-stimulating factor (GM-CSF), or a combination. Dexamethasone suppressed production of IL-1 alpha, TNF-alpha, and MIP-1 alpha; GM-CSF reduced secretion slightly but antagonized dexamethasone suppression when the two were given in combination. Cortisone acetate gave results similar to dexamethasone, but cortisone acetate suppression of BAM responses lasted 7 days, > or = 4 days longer than dexamethasone suppression. The effect of GM-CSF on cortisone acetate suppression lasted at least 7 days. GM-CSF could promote resistance to conidia by maintaining proinflammatory responses.

    View details for Web of Science ID 000180884500025

    View details for PubMedID 12599092

  • A murine model of coccidioidal meningitis JOURNAL OF INFECTIOUS DISEASES Kamberi, P., Sobel, R. A., Clemons, K. V., Stevens, D. A., Pappagianis, D., Williams, P. L. 2003; 187 (3): 453-460

    Abstract

    Coccidioidal meningitis is lethal in humans. A reproducible murine model was established by lumbar intrathecal injection of Coccidioides immitis arthroconidia. Cerebrospinal fluid (CSF) samples were obtained by cisternal puncture. Lethal infection developed in all mice given 10-60 colony-forming units (cfu). Lethargy, ataxia, or paralysis preceded death. Temporal studies after challenge with 27 cfu revealed positive brain (4/5 mice) and spinal cord (2/5 mice) cultures on day 3; CSF samples contained 688 leukocytes/mm(3) and 33 cfu/mL. The results of histopathologic analysis were unremarkable. By day 8, all mice were culture positive (5.0 log(10) cfu in brain tissue and 4.1 log(10) cfu in spinal cord tissue); CSF samples contained 4833 leukocytes/mm(3) and 3425 cfu/mL. Histopathologic examinations showed acute meningitis of the brain and spinal cord, some parenchymal invasion and abscesses, and meningeal arteritis. Groups of mice given ketoconazole had prolonged survival and suppressed lung disease; histopathologic examination demonstrated granulomatous meningitis, possibly a more chronic form. With the development of these models, studies of pathogenesis, host response, and therapy are possible.

    View details for Web of Science ID 000180636800013

    View details for PubMedID 12552429

  • Efficacy of amphotericin B or itraconazole in a murine model of central nervous system Aspergillus infection ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Chiller, T. M., Sobel, R. A., Luque, J. C., Clemons, K. V., Stevens, D. A. 2003; 47 (2): 813-815

    Abstract

    Given the greater than 90% lethality of clinical central nervous system (CNS) aspergillosis despite current therapies, there is a need for an animal model to study therapeutic strategies. We previously established a model of CNS aspergillosis by intracerebral infection and report here the results of treatment with the two therapies with the greatest clinical experience, i.e., treatments with amphotericin B (AMB) and itraconazole (ITZ). Mice were given cyclophosphamide to produce pancytopenia. AMB was given intraperitoneally (i.p.; 3 mg/kg of body weight) or intravenously (i.v.; 0.8 mg/kg) once daily. ITZ in cyclodextrin was given by gavage once daily at a dose of 100 mg/kg or twice daily at 50 mg/kg. Treatments were started at day 1 postinfection and given for 10 days. At day 15, survivors were euthanatized. Ninety percent of the mice given no treatment died by day 6, and 100% died by day 10. Mice treated with AMB either i.p. or i.v. had 40% survival. Mice treated with ITZ either once or twice per day had a median survival time of 10 days, compared with 4 days for control animals, but a survival rate of only 10%. AMB and ITZ prolonged survival (P, <0.0001 to <0.05) compared with controls. Brains from surviving mice had CFU of Aspergillus fumigatus. This model can be used to compare newer antifungals and to study combination therapy or immunotherapy to find better therapeutic alternatives.

    View details for DOI 10.1128/AAC.47.2.813-815.2003

    View details for Web of Science ID 000180646800058

    View details for PubMedID 12543700

  • Antifungal drug resistance CLINICAL INFECTIOUS DISEASES Loeffler, J., Stevens, D. A. 2003; 36: S31-S41

    Abstract

    The increasing incidence of invasive fungal infections is the result of many factors, including an increasing number of patients with severe immunosuppression. Although new drugs have been introduced to combat this problem, the development of resistance to antifungal drugs has become increasingly apparent, especially in patients who require long-term treatment or who are receiving antifungal prophylaxis, and there is growing awareness of shifts of flora to more-resistant species. The frequency, interpretation, and, in particular, mechanism of resistance to current classes of antifungal agents, particularly the azoles (where resistance has climbed most prominently) are discussed in this review.

    View details for Web of Science ID 000180334200005

    View details for PubMedID 12516028

  • Levels of matrix metalloproteinase-9 within cerebrospinal fluid in a rabbit model of coccidioidal meningitis and vasculitis JOURNAL OF INFECTIOUS DISEASES Williams, P. L., Leib, S. L., Kamberi, P., Leppert, D., Sobel, R. A., Bifrare, Y. D., Clemons, K. V., Stevens, D. A. 2002; 186 (11): 1692-1695

    Abstract

    Matrix metalloproteinase (MMP)-9 is produced by the central nervous system and inflammatory cells in a variety of inflammatory conditions in both animals and humans. MMP-9 promotes inflammation, breakdown of the blood-brain barrier, and vasculitis. Because vasculitis is seen frequently in patients with coccidioidal meningitis (CM), this study evaluated the presence of MMP-9 within the cerebrospinal fluid (CSF) of rabbits infected intracisternally with Coccidioides immitis arthroconidia. Infected rabbits demonstrated systemic and neurological sequelae to infection, including CSF pleocytosis. Levels of MMP-9 within CSF were assayed by use of zymography and compared with MMP-2 levels, which served as an internal control. Elevated levels of MMP-9 were detectable by day 3, continued to increase through day 10, and declined by day 15 after infection. MMP-9 may contribute to inflammation and vasculitis in this animal model. Future work can focus on evaluation of MMP inhibitors, to gain a better perspective of the role of this MMP in CM.

    View details for Web of Science ID 000179144900023

    View details for PubMedID 12447750

  • DNA binding compounds targeting fungal pathogens: an emerging concept in the discovery of novel antifungal agents. Current opinion in investigational drugs Lou, L., Velligan, M., Roberts, C., Stevens, D. A., Clemons, K. V. 2002; 3 (10): 1437-1445

    Abstract

    With the urgent need for novel agents to combat emerging fungal resistance to existing drugs, activity in the exploration of small molecule DNA binders has increased. Recently, selected cationic heterocyclic compounds belonging to a broad class of molecules known to bind to the minor groove of DNA were revealed to have potent antifungal activity. These molecules are different from the conventional DNA-interacting drugs such as topoisomerase inhibitors, DNA alkylators or intercalators. Selected compounds are fungicidal towards a variety of pathogenic yeasts and molds, and a selected lead compound is efficacious in a mouse model of systemic candidosis.

    View details for PubMedID 12431015

  • Zeamatin, clotrimazole and nikkomycin Z in therapy of a Candida vaginitis model JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY Stevens, D. A., Calderon, L., Martinez, M., Clemons, K. V., Wilson, S. J., Selitrennikoff, C. P. 2002; 50 (3): 361-364

    Abstract

    To study the interaction of antifungal drugs in topical therapy.Local therapy of Candida vaginitis with drugs alone and in combination was examined in a murine model. Zeamatin, a natural plant-derived antifungal protein, was tested alone and in combination with an azole, clotrimazole or nikkomycin Z, a chitin synthase inhibitor.Whereas alone, zeamatin was ineffective, nikkomycin Z was effective only when dosed multiple times per day, and clotrimazole efficacy was variable when administered in experimental vehicles (unlike the complex and undefined commercial preparation), zeamatin enhanced the efficacy of either of the other two drugs when they were given in combination.Drug interactions between novel drugs with unique mechanisms of action should be explored further, and may lead to more potent regimens.

    View details for DOI 10.1093/jac/dkf136

    View details for Web of Science ID 000177999000007

    View details for PubMedID 12205060

  • Development of a murine model of cerebral aspergillosis JOURNAL OF INFECTIOUS DISEASES Chiller, T. M., Luque, J. C., Sobel, R. A., Farrokhshad, K., Clemons, K. V., Stevens, D. A. 2002; 186 (4): 574-577

    Abstract

    Central nervous system (CNS) Aspergillus infection has a mortality rate in humans that approaches 95%. Because no animal models are available for studying this infection, we sought to develop a murine model of CNS aspergillosis. Inconsistent data were obtained for nonimmunosuppressed CD-1, C57BL/6, and DBA/2N mice after infection by midline intracranial injection of Aspergillus fumigatus. CD-1 mice given cyclophosphamide to produce immunosuppression had continuous pancytopenia. Dose-finding studies in CD-1 mice showed that infection with 5 x 106 conidia/mouse consistently caused 100% mortality by day 5-8; no mice died before day 3. Histologic examination of samples of brain tissue showed focal abscesses containing Aspergillus hyphae. Fungus burdens in brain were higher than those in other organs, although Aspergillus disseminated to the kidneys and the spleen. The model we established provides an opportunity to study immune responses to and therapeutic options for CNS disease in an immunologically defined, genetically manipulable, and inexpensive species.

    View details for Web of Science ID 000177271200020

    View details for PubMedID 12195389

  • Efficacy of intravenous liposomal amphotericin B (AmBisome) against coccidioidal meningitis in rabbits ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Clemons, K. V., Sobel, R. A., Williams, P. L., Pappagianis, D., Stevens, D. A. 2002; 46 (8): 2420-2426

    Abstract

    The efficacy of intravenously administered liposomal amphotericin B (AmBisome [AmBi]) for the treatment of experimental coccidioidal meningitis was compared with those of oral fluconazole (FLC) and intravenously administered conventional amphotericin B (AMB). Male New Zealand White rabbits were infected by intracisternal inoculation of arthroconidia of Coccidioides immitis. Starting 5 days postinfection, animals received one of the following: 5% dextrose water diluent; AMB given at 1 mg/kg of body weight; AmBi given at 7.5, 15, or 22.5 mg/kg intravenously three times per week for 3 weeks; or oral FLC given at 80 mg/kg for 19 days. One week after the cessation of therapy, all survivors were euthanatized, the numbers of CFU remaining in the spinal cord and brain were determined, and histological analyses were performed. All AmBi-, FLC-, or AMB-treated animals survived and had prolonged lengths of survival compared with those for the controls (P < 0.0001). Treated groups had significantly lower numbers of white blood cells and significantly lower protein concentrations in the cerebrospinal fluid compared with those for the controls (P < 0.01 to 0.0005) and had fewer clinical signs of infection (e.g., weight loss, elevated temperature, and neurological abnormalities including motor abnormalities). The mean histological scores for AmBi-treated rabbits were lower than those for FLC-treated and control rabbits (P < 0.016 and 0.0005, respectively); the scores for AMB-treated animals were lower than those for the controls (P < 0.0005) but were similar to those for FLC-treated rabbits. All regimens reduced the numbers of CFU in the brain and spinal cord compared with those for the controls (P < or =0.0005). AmBi-treated animals had 3- to 11-fold lower numbers of CFU than FLC-treated rabbits and 6- to 35-fold lower numbers of CFU than AmB-treated rabbits. Three of eight animals given 15 mg of AmBi per kg had no detectable infection in either tissue, whereas other doses of AmBi or FLC cleared either the brain or the spinal cord of infection in fewer rabbits. In addition, clearance of the infection from both tissues was achieved in none of the rabbits, and neither tissue was cleared of infection in AMB-treated animals. Overall, these data indicate that intravenously administered AmBi is superior to oral FLC or intravenous AMB and that FLC is better than AMB against experimental coccidioidal meningitis. These data indicate that AmBi may offer an improvement in the treatment of coccidioidal meningitis. Additional studies are warranted.

    View details for DOI 10.1128/AAC.46.8.2420-2426.2002

    View details for Web of Science ID 000176968700016

    View details for PubMedID 12121913

  • Regulation of bronchoalveolar macrophage proinflammatory cytokine production by dexamethasone and granulocyte-macrophage colony-stimulating factor after stimulation by Aspergillus conidia or lipopolysaccharide CYTOKINE Kamberi, M., Brummer, E., Stevens, D. A. 2002; 19 (1): 14-20

    Abstract

    There is substantial evidence that local production of proinflammatory cytokines are very important in host resistance to aspergillosis. Dexamethasone (DEX) down-regulates production of these cytokines by stimulated bronchoalveolar macrophages (BAM) and constitutes a risk factor for aspergillosis. Granulocyte-macrophage colony-stimulating factor (GM-CSF) antagonizes DEX suppression of antifungal activity by BAM. Here we investigated the possibility that GM-CSF could antagonize DEX down-regulation of interleukin (IL)-1alpha and tumour necrosis factor (TNF)-alpha production by stimulated BAM. Control BAM responded to increasing numbers of conidia of Aspergillus fumigatus with increasing production of IL-1 and TNF. DEX (10(-7)M) significantly suppressed IL-1 and TNF production by BAM+conidia. Although GM-CSF did not enhance IL-1 or TNF production by BAM+conidia, GM-CSF significantly antagonized DEX suppression of IL-1 cytokine production. For comparative purposes, lipopolysaccharide (LPS, 1 microg/ml) was used to stimulate BAM in experiments similar to the above. In contrast to the findings with conidia, GM-CSF enhanced the production of IL-1 (5-fold) and TNF (1.5-fold) by LPS treated BAM. DEX suppression of cytokine production by BAM+LPS was modestly but significantly antagonized by GM-CSF. Moreover, differences between regulation of IL-1 and TNF production by BAM+conidia or LPS and peritoneal macrophages (PM)+conidia or LPS were documented. Finally, the anti-inflammatory cytokine IL-10 was minimally produced by BAM + conidia or LPS, but IL-10 was produced by PM + conidia or LPS. In summary, these data indicate that the risk factor for aspergillosis associated with DEX could be lessened in the pulmonary compartment with GM-CSF. On the other hand, desired effects of DEX could be maintained in other compartments.

    View details for DOI 10.1006/cyto.2002.1049

    View details for Web of Science ID 000178273100003

    View details for PubMedID 12200108

  • Molecular epidemiology of Candida JOURNAL OF CLINICAL MICROBIOLOGY Stevens, D. A. 2002; 40 (7): 2710-2710

    View details for DOI 10.1128/JCM.40.7.2710.2002

    View details for Web of Science ID 000176605800079

    View details for PubMedID 12089319

  • fos-1, a putative histidine kinase as a virulence factor for systemic aspergillosis MEDICAL MYCOLOGY Clemons, K. V., Miller, T. K., Selitrennikoff, C. P., Stevens, D. A. 2002; 40 (3): 259-262

    Abstract

    In fungi, two-component histidine kinases have various functions including regulation of osmosensitivity, and of cell-wall assembly. Furthermore, one of these proteins, cos-1, has been shown to be important for virulence of Candida albicans. Recently, a putative histidine kinase, fos-1, has been isolated and partially characterized from Aspergillus fumigatus. Here we compare the virulence of a fos-1 deletion strain with that of the parental wild-type strain in a murine model of systemic aspergillosis. Our results show that the fos-1 deletion strain has significantly reduced virulence as compared with the parental wild-type strain. Thus, we propose that the fos-1 two-component histidine kinase is a virulence factor of A. fumigatus.

    View details for Web of Science ID 000177080400004

    View details for PubMedID 12146755

  • Resistance mechanisms in clinical isolates of Candida albicans ANTIMICROBIAL AGENTS AND CHEMOTHERAPY White, T. C., Holleman, S., Dy, F., Mirels, L. F., Stevens, D. A. 2002; 46 (6): 1704-1713

    Abstract

    Resistance to azole antifungals continues to be a significant problem in the common fungal pathogen Candida albicans. Many of the molecular mechanisms of resistance have been defined with matched sets of susceptible and resistant clinical isolates from the same strain. Mechanisms that have been identified include alterations in the gene encoding the target enzyme ERG11 or overexpression of efflux pump genes including CDR1, CDR2, and MDR1. In the present study, a collection of unmatched clinical isolates of C. albicans was analyzed for the known molecular mechanisms of resistance by standard methods. The collection was assembled so that approximately half of the isolates were resistant to azole drugs. Extensive cross-resistance was observed for fluconazole, clotrimazole, itraconazole, and ketoconazole. Northern blotting analyses indicated that overexpression of CDR1 and CDR2 correlates with resistance, suggesting that the two genes may be coregulated. MDR1 overexpression was observed infrequently in some resistant isolates. Overexpression of FLU1, an efflux pump gene related to MDR1, did not correlate with resistance, nor did overexpression of ERG11. Limited analysis of the ERG11 gene sequence identified several point mutations in resistant isolates; these mutations have been described previously. Two of the most common point mutations in ERG11 associated with resistance, D116E and E266D, were tested by restriction fragment length polymorphism analysis of the isolates from this collection. The results indicated that the two mutations occur frequently in different isolates of C. albicans and are not reliably associated with resistance. These analyses emphasize the diversity of mechanisms that result in a phenotype of azole resistance. They suggest that the resistance mechanisms identified in matched sets of susceptible and resistant isolates are not sufficient to explain resistance in a collection of unmatched clinical isolates and that additional mechanisms have yet to be discovered.

    View details for DOI 10.1128/AAC.46.6.1704-1713.2002

    View details for Web of Science ID 000175662800014

    View details for PubMedID 12019079

  • Correlation of the frequency of petite formation by isolates of Saccharomyces cerevisiae with virulence MEDICAL MYCOLOGY Weger, S. D., Ganji, A., Clemons, K. V., Byron, J. K., Minn, Y., Stevens, D. A. 2002; 40 (2): 161-168

    Abstract

    In previous studies on the colony phenotype switching of Saccharomyces cerevisiae, we observed that the least virulent isolates formed greater numbers of petite colonies when grown at body temperature, 37 degrees C. To determine if there is a link between virulence and petite formation, we examined the frequency of spontaneous petite formation for virulent clinical isolates (YJM128, YJM309), an intermediate virulent segregant of YJM128 (YJM145) and avirulent clinical (YJM308) and nonclinical S. cerevisiae (Y55, YJM237) after growth at 37 degrees C. The rank order of increasing frequency of petite formation was YJM128 = YJM145 < YJM309 < Y 55 < YJM308 = YJM237, which is similar to the rank-order of virulence in CD-1 mice. To assess the virulence of petites in vivo, two mouse models, CD-1 and DBA/ 2N, were infected i.v. with 10(7) cfu of either the parental grand or a spontaneously derived petite from one of four isolates previously classified with differing degrees of virulence: YJM128, YJM309, YJM145 and Y55. In both CD-1 and DBA/2N, the mean log10 cfu of grands recovered from the brain was significantly higher than that of the petites (P<0001). Overall, petites were significantly less virulent than the parental strains. However, death of some DBA/2N mice caused by YJM128 petite 1 showed that petites are not totally avirulent. To see if S. cerevisiae isolates form petite colonies in vivo, both mouse models were infected with parental grands of YJM128 and Y55. Recovered colonies were counted and confirmed as grand or petite, and the frequency of petite colonies in the brain, the target organ, correlated with the in vitro results. Overall, these studies show an inverse correlation between the frequency of petite-colony formation and the previously determined virulence of S. cerevisiae in CD-1 mice. Furthermore, petites were significantly less virulent than the parental grands, in most cases, and petites are spontaneously formed in vivo at a frequency inversely correlated to the virulence of the strain.

    View details for Web of Science ID 000175665800008

    View details for PubMedID 12058729

  • Homozygosity at the Candida albicans MTL locus associated with azole resistance MICROBIOLOGY-SGM Rustad, T. R., Stevens, D. A., Pfaller, M. A., White, T. C. 2002; 148: 1061-1072

    Abstract

    Antifungal drug resistance in the pathogenic fungus Candida albicans is a serious threat to the growing population of immunocompromised patients. This study describes a significant correlation between loss of heterozygosity at the C. albicans mating-type-like (MTL) locus and resistance to azole antifungals. A pool of 96 clinical isolates consisting of 50 azole-resistant or susceptible dose-dependent isolates and 46 azole-susceptible isolates was screened by PCR for the presence of MTLa1 and MTLalpha1. These genes were used as markers for the MTLa and MTLalpha loci. Both loci were present in 84 of the isolates. Six isolates failed to amplify MTLa1 and six failed to amplify MTLalpha1. Further PCR analysis demonstrated that loss of the MTLa1 and MTLalpha1 genes corresponded to loss of all of the loci-specific genes, resulting in homozygosity at the MTL locus. Southern analysis and single nucleotide polymorphism (SNP) analysis were used to determine that this loss of heterogeneity was due to replacement of one of the MTL loci with a duplicate of the other locus resulting in two homozygous copies of the MTL locus. Of the 12 homozygous isolates, one isolate was sensitive to azole drugs. Statistical analysis of the data demonstrates a strong correlation between homozygosity at the MTL locus and azole resistance (P<0 small middle dot003). In a set of serial isolates, an increase in azole resistance correlated with the loss of heterozygosity at the MTL locus, lending further strength to the correlation. Gene disruptions of the MTL loci were found to have no effect on azole susceptibility.

    View details for Web of Science ID 000175084400015

    View details for PubMedID 11932451

  • Experimental Paracoccidioides brasiliensis infection in mice: influence of the hormonal status of the host on tissue responses MEDICAL MYCOLOGY Aristizabal, B. H., Clemons, K. V., Cock, A. M., Restrepo, A., Stevens, D. A. 2002; 40 (2): 169-178

    Abstract

    We have previously proposed that 17beta-estradiol may be responsible in part for the decreased frequency of clinical paracoccidioidomycosis in females via a blocking of the initial morphological transformation necessary to initiate infection. Here we examined the course of infection in male and female mice in relation to their hormonal status. After pulmonary infection with conidia, normal males showed progressive infection, whereas normal females restricted proliferation and progressive disease. In contrast, castrated animals exhibited lesser capacity to restrict disease progression. Castrated male mice reconstituted with 17beta-estradiol initially restricted proliferation, but showed disease progression later in infection, whereas castrated female mice reconstituted with testosterone were unable to restrict disease. Quantitative histological analyses demonstrated that only normal male and castrated reconstituted mice developed granulomas, which decreased in number and size with time correlating with increasing numbers of CFU in the lungs. Greater numbers of chronic inflammatory foci did not correlate with higher CFU. These results further support a role for 17beta-estradiol during early innate resistance of females to paracoccidioidomycosis.

    View details for Web of Science ID 000175665800009

    View details for PubMedID 12058730

  • Efficacy of ravuconazole in treatment of systemic murine histoplasmosis ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Clemons, K. V., Martinez, M., Calderon, L., Stevens, D. A. 2002; 46 (3): 922-924

    Abstract

    Ravuconazole (RCZ) was evaluated for efficacy in comparison to fluconazole (FCZ) and itraconazole (ITZ) in murine models of disseminated histoplasmosis. All regimens tested prolonged survival (P < 0.05 to 0.0001). At equivalent doses of 50 mg/kg of body weight, RCZ and ITZ were equally effective and RCZ was more effective than FCZ (P = 0.02). Clearance of fungal burden from the livers and spleens of mice showed RCZ and ITZ at doses of 50 mg/kg to be efficacious but not curative. These data indicate that RCZ should be studied further.

    View details for DOI 10.1128/AAC.46.3.922-924.2002

    View details for Web of Science ID 000173908900052

    View details for PubMedID 11850289

  • Protection of peritoneal macrophages by granulocyte/macrophage colony-stimulating factor (GM-CSF) against dexamethasone suppression of killing of Aspergillus, and the effect of human GM-CSF MICROBES AND INFECTION Brummer, E., Maqbool, A., Stevens, D. A. 2002; 4 (2): 133-138

    Abstract

    Murine peritoneal macrophages in vitro could kill Aspergillus fumigatus conidia, and this activity could be suppressed with dexamethasone. Treatment with granulocyte/macrophage colony-stimulating factor (GM-CSF) alone did not boost killing, but GM-CSF treatment concurrently with dexamethasone reversed the dexamethasone suppression. Both recombinant human and recombinant murine GM-CSF were equivalent in this activity, even though the human reagent reportedly does not stimulate differentiation of murine stem cells. Recombinant human GM-CSF could also reverse dexamethasone suppression of bronchoalveolar macrophage conidiacidal activity. Sequential studies with peritoneal macrophages indicated that recombinant human GM-CSF pretreatment also blocked dexamethasone suppression, but the GM-CSF treatment given after dexamethasone did not block the suppressive effect. Recombinant human GM-CSF did not boost spleen cell proliferation to a mitogenic stimulus, and did not reverse dexamethasone suppression of proliferation. These studies suggest GM-CSF treatment prior to and concurrent with steroid immunosuppression may ameliorate the steroid effect on tissue macrophage antifungal activity, but does not affect steroid suppression of T-cell immunity.

    View details for Web of Science ID 000174578300002

    View details for PubMedID 11880043

  • Effect of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor on polymorphonuclear neutrophils, monocytes or monocyte-derived macrophages combined with voriconazole against Cryptococcus neoformans MEDICAL MYCOLOGY Chiller, T., Farrokhshad, K., Brummer, E., Stevens, D. A. 2002; 40 (1): 21-26

    Abstract

    The antifungal activity of voriconazole (VCZ) was tested against Cryptococcus neoformans (Cn) with and without the addition of polymorphonuclear neutrophils (PMN), monocytes or monocyte-derived macrophages (MDM) in vitro. Human effector cells with and without the addition of VCZ were incubated with Cn for 24 h. PMN, mono and MDM alone resulted in 61%, 34% and 23% inhibition of Cn, respectively (n = 3, P<0.01). VCZ at 0.01 and 0.05 microg ml(-1) alone resulted in 48% inhibition and 19% killing (n = 6). The addition of VCZ at 0.01 and 0.05 microg ml(-1) to human effector cells enhanced killing of Cn by 51% and 71% for the PMN, 41% and 58% for the mono, and 14% and 34% for the MDM, respectively. The addition of either granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony stimulating factor (GM-CSF) significantly enhanced the ability of human effector cells to kill Cn. G-CSF and GM-CSF plus PMN resulted in 47% and 46% killing, respectively; GM-CSF plus monocytes or MDM resulted in 31% or 22% killing, respectively. G-CSF and GM-CSF further enhanced the collaborative killing effect of human effector cells and VCZ. At 0.01 and 0.05 microg ml(-1) of VCZ, G-CSF or GM-CSF enhanced PMN killing to 92% and 93% or 87% and 94%, respectively. GM-CSF enhanced both mono and MDM with VCZ at 0.01 and 0.05 microg ml(-1) in killing Cn to 62% and 86%, and 61% and 84%, respectively. These results suggest that VCZ would have good efficacy in the treatment of Cn infection in humans. Furthermore, VCZ would have enhanced efficacy in clinical settings where either G-CSF or GM-CSF was being used.

    View details for Web of Science ID 000173949300004

    View details for PubMedID 11860010

  • Defining opportunistic invasive fungal infections in immunocompromised patients with cancer and hematopoietic stem cell transplants: An international consensus CLINICAL INFECTIOUS DISEASES Ascioglu, S., Rex, J. H., de Pauw, B., BENNETT, J. E., Bille, J., Crokaert, F., Denning, D. W., Donnelly, J. P., Edwards, J. E., Erjavec, Z., Fiere, D., Lortholary, O., Maertens, J., Meis, J. F., Patterson, T. F., Ritter, J., Selleslag, D., Shah, P. M., Stevens, D. A., Walsh, T. J. 2002; 34 (1): 7-14

    Abstract

    During the past several decades, there has been a steady increase in the frequency of opportunistic invasive fungal infections (IFIs) in immunocompromised patients. However, there is substantial controversy concerning optimal diagnostic criteria for these IFIs. Therefore, members of the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group formed a consensus committee to develop standard definitions for IFIs for clinical research. On the basis of a review of literature and an international consensus, a set of research-oriented definitions for the IFIs most often seen and studied in immunocompromised patients with cancer is proposed. Three levels of probability are proposed: "proven," "probable," and "possible." The definitions are intended for use in the context of clinical and/or epidemiological research, not for clinical decision making.

    View details for Web of Science ID 000172543800007

    View details for PubMedID 11731939

  • The impact of culture isolation of Aspergillus species: A hospital-based survey of aspergillosis CLINICAL INFECTIOUS DISEASES Perfect, J. R., Cox, G. M., Lee, J. Y., Kauffman, C. A., de Repentigny, L., Chapman, S. W., Morrison, V. A., Pappas, P., Hiemenz, J. W., Stevens, D. A. 2001; 33 (11): 1824-1833

    Abstract

    The term "aspergillosis" comprises several categories of infection: invasive aspergillosis; chronic necrotizing aspergillosis; aspergilloma, or fungus ball; and allergic bronchopulmonary aspergillosis. In 24 medical centers, we examined the impact of a culture positive for Aspergillus species on the diagnosis, risk factors, management, and outcome associated with these diseases. Most Aspergillus culture isolates from nonsterile body sites do not represent disease. However, for high-risk patients, such as allogeneic bone marrow transplant recipients (60%), persons with hematologic cancer (50%), and those with signs of neutropenia (60%) or malnutrition (30%), a positive culture result is associated with invasive disease. When such risk factors as human immunodeficiency virus infection (20%), solid-organ transplantation (20%), corticosteroid use (20%), or an underlying pulmonary disease (10%) are associated with a positive culture result, clinical judgment and better diagnostic tests are necessary. The management of invasive aspergillosis remains suboptimal: only 38% of patients are alive 3 months after diagnosis. Chronic necrotizing aspergillosis, aspergilloma, and allergic bronchopulmonary aspergillosis have variable management strategies and better short-term outcomes.

    View details for Web of Science ID 000171998800004

    View details for PubMedID 11692293

  • Protection of bronchoalveolar macrophages by granulocyte-macrophage colony-stimulating factor against dexamethasone suppression of fungicidal activity for Aspergillus fumigatus conidia MEDICAL MYCOLOGY Brummer, E., Maqbool, A., Stevens, D. A. 2001; 39 (6): 509-515

    Abstract

    The objectives of this study were to: (i) see if granulocyte macrophage colony-stimulating factor (GM-CSF) could protect bronchoalveolar macrophages (BAM) against suppression by dexamethasone (DEX) and (ii) test the combined effect of GM-CSF and DEX on lymphocyte responses. Murine BAM killed Aspergillus fumigatus conidia by 33 +/- 4% (mean +/- SD) in a 2.5-h assay, unaffected by GM-CSF treatment. Killing by BAM treated with DEX (10(-7) M) for 48 h in vitro was reduced to 13 +/- 6%; however, if GM-CSF (500 U ml(-1)) was present during DEX treatment of BAM, killing of conidia (33 +/- 2%) by BAM was preserved. By contrast, DEX suppression of lymphocyte responses to concanavalin A was maintained during co-culture with GM-CSF. In sequence treatment experiments, initial treatment of BAM with GM-CSF protected against subsequent treatment with DEX. When macrophages were pretreated with DEX, GM-CSF could reverse suppression even when added subsequently, provided DEX treatment was discontinued. These data suggest that it may be possible to suppress lymphocyte responses with DEX, yet at the same time maintain BAM defenses with GM-CSF against pulmonary infections by conidia of A. fumigatus.

    View details for Web of Science ID 000172929200007

    View details for PubMedID 11798056

  • Efficacy of ravueonazole in treatment of mucosal candidosis in SCID mice ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Clemons, K. V., STEVENS, D. 2001; 45 (12): 3433-3436

    Abstract

    A model of orogastric candidosis in SCID mice, which mimics disease seen in AIDS patients, was used to evaluate ravuconazole in comparison with fluconazole for treatment. Mice were infected orally with Candida albicans and received either no treatment or oral treatment once daily for 12 days with 1, 5, or 25 mg of ravuconazole per kg of body weight per day, 5 or 25 mg of fluconazole per kg per day, or diluent (10% dimethyl sulfoxide in 0.5% carboxymethyl cellulose). The numbers of C. albicans CFU in the esophagus, stomach, small intestine, and cecum on day 25 in mice given no treatment and diluent were equivalent. Both doses of fluconazole significantly reduced numbers of CFU in all four tissues but were equivalent to each other. Ravuconazole showed dose-responsive improvement of clearance of CFU. Ravuconazole at 25 mg/kg was superior in reduction of numbers of CFU in all tissues to controls or 25 mg of fluconazole per kg and to other regimens in at least three tissues. Fluconazole at 25 mg/kg cured no infection in any tissue, whereas 25 mg of ravuconazole/kg cleared infection in all tissues from 50% of mice. Ravuconazole has good efficacy and the potential to cure mucosal candidosis in the absence of a functional immune response.

    View details for Web of Science ID 000172304800023

    View details for PubMedID 11709320

  • Intrathecal amphotericin in the management of coccidioidal meningitis. Seminars in respiratory infections Stevens, D. A., Shatsky, S. A. 2001; 16 (4): 263-269

    Abstract

    Coccidioidal meningitis is lethal in the absence of treatment. The advent of the azoles has not led to cure, causing many clinicians to revert to intra-cerebrospinal fluid (CSF) amphotericin as part of the treatment regimen, desiring the influence of the latter regimen's ability to clear infection more completely and rapidly. Intra-CSF amphotericin therapy is, however, far more toxic than oral azoles and requires much more clinical management to achieve success and avoid toxicity. This management task increasingly, for insurance reasons or geographic reasons, falls on clinicians unfamiliar with the disease. We delineate our experience in the medical and surgical management of this form of therapy, including procedural details that we have found useful, for the benefit of our colleagues who may wish to use them. As ours is a teaching institution, we have found this material also useful for physicians in training, who are learning about the treatment of these patients.

    View details for PubMedID 11740828

  • In vivo GM-CSF prevents dexamethasone suppression of killing of Aspergillus fumigatus conidia by bronchoalveolar macrophages JOURNAL OF LEUKOCYTE BIOLOGY Brummer, E., Maqbool, A., Stevens, D. A. 2001; 70 (6): 868-872

    Abstract

    Dexamethasone (DEX) is a potent immunosuppressive agent used in the treatment of several disorders. However, despite its beneficial effects, DEX puts patients at risk for opportunistic infections, especially pulmonary aspergillosis. Previously we reported that in vitro granulocyte-macrophage colony-stimulating factor (GM-CSF) blocks the immunosuppressive action of DEX on bronchoalveolar macrophages (BAMs). Here we report that BAMs freshly isolated from mice treated intraperitoneally with DEX for 24 h had significantly (P<0.01) reduced killing of conidia, i.e., 15 +/- 5% conidia killed by BAMs from DEX-treated mice versus 35 +/- 3% by BAMs from mice given saline, 38 +/- 5% by BAMs from mice given GM-CSF, and 39 +/- 1% by BAMs from mice given both DEX and GM-CSF. On the other hand, in another compartment GM-CSF could not block the DEX reduction of spleen weight and spleen cellularity. Unlike GM-CSF, granulocyte colony-stimulating factor did not block DEX suppression of BAMs. GM-CSF given 24 h before DEX resulted in blocking of DEX suppression of BAM conidiacidal activity. However, when DEX was given 24 h before GM-CSF, DEX suppression of BAM was not reversed. These data show that GM-CSF in vivo blocks the in vivo immunosuppressive effects of DEX on BAM killing of conidia and suggest a potential use of GM-CSF in patients at risk for aspergillosis due to immunosuppressive DEX treatment.

    View details for Web of Science ID 000172586800004

    View details for PubMedID 11739548

  • The treatment of pulmonary aspergilloma. Current opinion in investigational drugs Judson, M. A., Stevens, D. A. 2001; 2 (10): 1375-1377

    Abstract

    Aspergillomas are fungal balls within lung cavities. The natural history of patients affected is variable. Hemoptysis is a dangerous sequela. Factors associated with a poor prognosis have been defined and therapy is difficult because of the lack of a blood supply. Randomized trials are lacking. Surgical treatment is definitive but many patients are ineligible. Percutaneous therapy and bronchial artery embolization is appropriate for some patients and itraconazole has produced favorable results in several studies.

    View details for PubMedID 11890350

  • Current pharmacotherapy of allergic bronchopulmonary aspergillosis. Expert opinion on pharmacotherapy Judson, M. A., Stevens, D. A. 2001; 2 (7): 1065-1071

    Abstract

    Although no well-designed studies have been carried out, the available data support the use of corticosteroids for acute exacerbations of allergic bronchopulmonary aspergillosis (ABPA). Neither the optimal steroid dose nor the duration of therapy has been standardised but limited data suggest the starting dose should be prednisone (approximately 0.5 mg/kg/day). The decision to taper steroids should be made on an individual basis, depending on clinical course. The available data suggest that clinical symptoms alone are inadequate to make such decisions, since significant lung damage may occur in asymptomatic patients. Increasing serum IgE levels, new or worsening infiltrate on chest radiograph and worsening spirometry suggest that steroids should be used. Multiple asthmatic exacerbations in a patient with ABPA suggest that chronic steroid therapy should be used. Itraconazole appears useful as a steroid sparing agent.

    View details for PubMedID 11583057

  • The interaction of human monocytes, monocyte-derived macrophages, and polymorphonuclear neutrophils with caspofungin (MK-0991), an echinocandin, for antifungal activity against Aspergillus fumigatus DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE Chiller, T., Farrokhshad, K., Brummer, E., Stevens, D. A. 2001; 39 (2): 99-103

    Abstract

    The collaboration between human effector cells and caspofungin (MK-0991), a 1,3-beta-D glucan synthase inhibitor, was studied for antifungal activity against Aspergillus fumigatus. Caspofungin was co-cultured for 24h with either human monocytes (Monos), monocyte-derived macrophages (MDM), or polymorphonuclear neutrophils (PMN) against germlings of A. fumigatus and antifungal activity assessed using the XTT metabolic assay. Caspofungin at 0.1 micorg/ml and 0.05 microg/ml or Monos alone against germlings caused significant inhibition. Microscopically this was correlated with less growth and stunted malformed hyphae. The addition of caspofungin at 0.1 microg/ml and 0.05 microg/ml to the monocyte cultures increased antifungal activity. The inhibition of the combination was significantly greater than drug alone (P <.01) and Monos alone (P <.01). MDM against Aspergillus germlings inhibited hyphal growth. The combination of caspofungin at 0.1 microg/ml and 0.05 microg/ml to the macrophage cultures increased antifungal activity. The growth inhibition by the combination was significantly greater than drug alone (P <.01) and MDM alone (P <.01). There was no significant interference with or enhancement of PMNs and caspofungin. These data support the activity of caspofungin against A. fumigatus in vitro, and indicates a cooperative activity with human effector cells. This suggests caspofungin in vivo would have increased efficacy as it combines with host defenses against A. fumigatus.

    View details for Web of Science ID 000167613000005

    View details for PubMedID 11248522

  • Influence of human sera on the in vitro activity of the echinocandin caspofungin (MK-0991) against Aspergillus fumigatus ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Chiller, T., Farrokhshad, K., Brummer, E., Stevens, D. A. 2000; 44 (12): 3302-3305

    Abstract

    There have been several reports that the activity of echinocandin antifungal agents is not affected or decreased in the presence of human sera. It is known that these drugs are bound >80% in animal and human sera. The activity of the echinocandin caspofungin (MK-0991), a 1,3-beta-D-glucan synthase inhibitor, against Aspergillus fumigatus with and without human sera was studied. Conidia of A. fumigatus in microtest plate wells formed germlings after overnight culture in RPMI 1640. Caspofungin was then added with or without serum, and the germlings were incubated at 37 degrees C for 24 h. Human serum (5%) in RPMI 1640 alone did not significantly inhibit the growth of A. fumigatus in vitro. Caspofungin in RPMI 1640 exhibited dose-dependent inhibition, with concentrations of 0.1 and 0.05 microg/ml inhibiting 24.9% +/- 10.4% and 11.7% +/- 3.6%, respectively (n = 10; P < 0.01). The addition of 5% human serum to caspofungin at 0.1 or 0.05 microg/ml increased the inhibition to 78.6% +/- 5.8% or 58.3% +/- 19.2%, respectively (n = 10; P < 0.01 versus controls and versus the drug without serum). Lower concentrations of serum also potentiated drug activity. The effect of human sera was further seen when using caspofungin that had lost activity (e.g., by storage) against A. fumigatus at 0.1 microg/ml. Inactive caspofungin alone demonstrated no significant inhibition of hyphal growth, whereas the addition of 5% human serum to the inactive drug showed 83% +/- 16.5% inhibition (n = 5; P < 0. 01). The restoration of activity of caspofungin was seen at concentrations as low as 0.05% human serum. In contrast to prior reports, this study suggests that human serum acts synergistically with caspofungin to enhance its inhibitory activity in vitro against A. fumigatus.

    View details for Web of Science ID 000167156500009

    View details for PubMedID 11083631

  • Drug interaction studies of a glucan synthase inhibitor (LY 303366) and a chitin synthase inhibitor (nikkomycin Z) for inhibition and killing of fungal pathogens ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Stevens, D. A. 2000; 44 (9): 2547-2548

    Abstract

    The interaction between inhibitors of components of the fungal cell wall, glucan and chitin, was studied in vitro with the respective synthase enzyme inhibitors LY 303366 and nikkomycin Z. With Aspergillus fumigatus synergy was noted for inhibition and killing, and synergistic activity was also noted for some isolates of other species presently regarded as difficult to treat.

    View details for Web of Science ID 000088830900054

    View details for PubMedID 10952614

  • Practice guidelines for diseases caused by Aspergillus CLINICAL INFECTIOUS DISEASES Stevens, D. A., Kan, V. L., Judson, M. A., Morrison, V. A., Dummer, S., Denning, D. W., BENNETT, J. E., Walsh, T. J., Patterson, T. F., Pankey, G. A. 2000; 30 (4): 696-709

    Abstract

    Aspergillosis comprises a variety of manifestations of infection. These guidelines are directed to 3 principal entities: invasive aspergillosis, involving several organ systems (particularly pulmonary disease); pulmonary aspergilloma; and allergic bronchopulmonary aspergillosis. The recommendations are distilled in this summary, but the reader is encouraged to review the more extensive discussions in subsequent sections, which show the strength of the recommendations and the quality of the evidence, and the original publications cited in detail. Invasive aspergillosis. Because it is highly lethal in the immunocompromised host, even in the face of therapy, work-up must be prompt and aggressive, and therapy may need to be initiated upon suspicion of the diagnosis, without definitive proof (BIII). Intravenous therapy should be used initially in rapidly progressing disease (BIII). The largest therapeutic experience is with amphotericin B deoxycholate, which should be given at maximum tolerated doses (e.g., 1-1.5 mg/kg/d) and should be continued, despite modest increases in serum creatinine levels (BIII). Lipid formulations of amphotericin are indicated for the patient who has impaired renal function or who develops nephrotoxicity while receiving deoxycholate amphotericin (AII). Oral itraconazole is an alternative for patients who can take oral medication, are likely to be adherent, can be demonstrated (by serum level monitoring) to absorb the drug, and lack the potential for interaction with other drugs (BII). Oral itraconazole is attractive for continuing therapy in the patient who responds to initial iv therapy (CIII). Therapy should be prolonged beyond resolution of disease and reversible underlying predispositions (BIII). Adjunctive therapy (particularly surgery and combination chemotherapy, also immunotherapy), may be useful in certain situations (CIII). Aspergilloma. The optimal treatment strategy for aspergilloma is unknown. Therapy is predominantly directed at preventing life-threatening hemoptysis. Surgical removal of aspergilloma is definitive treatment, but because of significant morbidity and mortality it should be reserved for high-risk patients such as those with episodes of life-threatening hemoptysis, and considered for patients with underlying sarcoidosis, immunocompromised patients, and those with increasing Aspergillus-specific IgG titers (CIII). Surgical candidates would need to have adequate pulmonary function to undergo the operation. Bronchial artery embolization rarely produces a permanent success, but may be useful as a temporizing procedure in patients with life-threatening hemoptysis. Endobronchial and intracavitary instillation of antifungals or oral itraconazole may be useful for this condition. Since the majority of aspergillomas do not cause life-threatening hemoptysis, the morbidity and cost of treatment must be weighed against the clinical benefit. Allergic bronchopulmonary aspergillosis (APBA). Although no well-designed studies have been carried out, the available data support the use of corticosteroids for acute exacerbations of ABPA (AII). Neither the optimal corticosteroid dose nor the duration of therapy has been standardized, but limited data suggest the starting dose should be approximately 0.5 mg/kg/d of prednisone. The decision to taper corticosteroids should be made on an individual basis, depending on the clinical course (BIII). The available data suggest that clinical symptoms alone are inadequate to make such decisions, since significant lung damage may occur in asymptomatic patients. Increasing serum IgE levels, new or worsening infiltrate on chest radiograph, and worsening spirometry suggest that corticosteroids should be used (BII). Multiple asthmatic exacerbations in a patient with ABPA suggest that chronic corticosteroid therapy should be used (BIII). Itraconazole appears useful as a corticosteroid sparing agent (BII). (ABSTRACT TRUNCATED)

    View details for Web of Science ID 000087009000015

    View details for PubMedID 10770732

  • Cryptococcal meningitis in the immunocompromised host: intracranial hypertension and other complications MYCOPATHOLOGIA Stevens, D. A., Denning, D. W., Shatsky, S., Armstrong, R. W., Adler, J. D., Lewis, B. H. 1999; 146 (1): 1-8

    Abstract

    Cryptococcosis as a complication of the immunocompromised host has dramatically increased in frequency since the start of the AIDS epidemic. This trend has heightened awareness of the complications of cryptococcal meningitis; of these, intracranial hypertension is common, severe, and life-threatening, as exemplified by three cases in our institutions presented here in detail. An aggressive approach to management of this complication has not been the standard of care, but neurosurgical interventional studies combined with physiologic observations suggest early intervention may reduce the devastating morbidity and mortality.

    View details for Web of Science ID 000085132000001

    View details for PubMedID 10721514

  • Activity of voriconazole combined with neutrophils or monocytes against Aspergillus fumigatus: Effects of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Vora, S., Chauhan, S., Brummer, E., Stevens, D. A. 1998; 42 (9): 2299-2303

    Abstract

    Voriconazole (VCZ) was tested for antifungal activity against Aspergillus fumigatus hyphae alone or in combination with neutrophils or monocytes. Antifungal activity was measured as percent inhibition of hyphal growth in assays using the dye MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] or XTT [2, 3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxa nilide ]. With both assays, VCZ inhibited hyphal growth at concentrations of <1 microgram/ml and was almost as active as amphotericin B. VCZ (0.6 microgram/ml) was sporicidal, as was amphotericin B (0.4 microgram/ml). With both the MTT and XTT assays, neutrophils alone inhibited hyphae; when combined with VCZ, there was additive activity. Both granulocyte colony-stimulating factor- and granulocyte-macrophage colony-stimulating factor (GM-CSF)-treated polymorphonuclear neutrophils (PMN) had enhanced inhibition of hyphal growth. Moreover, such treatment of PMN also enhanced the collaboration of PMN with VCZ. Monocytes inhibited hyphal growth. When VCZ was combined with monocytes or monocytes were treated with GM-CSF, inhibition was significantly increased, to similar levels. However, the combination of VCZ with GM-CSF treatment of monocytes did not significantly increase the high-level inhibition by monocytes with either agent alone.

    View details for Web of Science ID 000075737400027

    View details for PubMedID 9736553

  • Direct allelic variation scanning of the yeast genome SCIENCE Winzeler, E. A., Richards, D. R., Conway, A. R., Goldstein, A. L., Kalman, S., McCullough, M. J., McCusker, J. H., Stevens, D. A., Wodicka, L., Lockhart, D. J., Davis, R. W. 1998; 281 (5380): 1194-1197

    Abstract

    As more genomes are sequenced, the identification and characterization of the causes of heritable variation within a species will be increasingly important. It is demonstrated that allelic variation in any two isolates of a species can be scanned, mapped, and scored directly and efficiently without allele-specific polymerase chain reaction, without creating new strains or constructs, and without knowing the specific nature of the variation. A total of 3714 biallelic markers, spaced about every 3.5 kilobases, were identified by analyzing the patterns obtained when total genomic DNA from two different strains of yeast was hybridized to high-density oligonucleotide arrays. The markers were then used to simultaneously map a multidrug-resistance locus and four other loci with high resolution (11 to 64 kilobases).

    View details for Web of Science ID 000075531200054

    View details for PubMedID 9712584

  • Cytokines and mycoses MEDICAL MYCOLOGY Stevens, D. A., Walsh, T. J., Bistoni, F., Cenci, E., Clemons, K. V., Del Sero, G., d'Ostiani, C. F., Kullberg, B. J., Mencacci, A., Roilides, E., Romani, L. 1998; 36: 174-182

    Abstract

    Cell-mediated immunity (CMI) has been shown, over many decades of clinical observation and bench research, to be central to the outcome of invasive fungal infections. In recent years, understanding the role of messenger molecules (cytokines), in coordinating and augmenting cellular immunity has been ascendant. These studies have made it possible to consider using cytokines, now available in abundant quantities via recombinant DNA technologies, to treat fungal infections. In this symposium, the most important fungal pathogens that cause infections in humans, particularly in immunocompromised patients, are considered, with emphasis on how recent experimental work may lead to a better understanding of the role of cytokines and their use in therapy.

    View details for Web of Science ID 000075665900020

    View details for PubMedID 9988506

  • Intergenic transcribed spacer PCR ribotyping for differentiation of Saccharomyces species and interspecific hybrids JOURNAL OF CLINICAL MICROBIOLOGY McCullough, M. J., Clemons, K. V., McCusker, J. H., Stevens, D. A. 1998; 36 (4): 1035-1038

    Abstract

    The taxonomy of the genus Saccharomyces has undergone significant changes recently with the use of genotypic rather than phenotypic methods for the identification of strains to the species level. The sequence of rRNA genes has been utilized for the identification of a variety of fungi to the species level. This methodology, applied to species of Saccharomyces, allows unknown Saccharomyces isolates to be assigned to the type strains. It was the aim of the present study to assess whether typing of the intergenic spacer region by using restriction fragment length polymorphisms of PCR products (intergenic transcribed spacer PCR [ITS-PCR] ribotyping) could distinguish among type strains of the 10 accepted species of Saccharomyces and further to assess if this method could distinguish strains that were interspecific hybrids. Cellular DNA, isolated after the lysis of protoplasts, was amplified by PCR using ITS1 and ITS4 primers, purified by liquid chromatography, and digested with restriction endonucleases. Ribotyping patterns using the restriction enzymes MaeI and HaeIII could distinguish all species of Saccharomyces from each other, as well as from Candida glabrata, Candida albicans, and Blastomyces dermatitidis. The only exception to this was the inability to distinguish between Saccharomyces bayanus and S. pastorianus (S. carlsbergensis). Furthermore, interspecific hybrids resulting from the mating of sibling species of Saccharomyces were shown to share the ITS-PCR ribotyping patterns of both parental species. It should now be possible, by this simple PCR-based technique, to accurately identify these strains to the species level, thereby allowing an increase in our understanding of the characteristics required by these interspecific hybrids for their particular ecological niches.

    View details for Web of Science ID 000072565800035

    View details for PubMedID 9542932

  • Epidemiological investigation of vaginal Saccharomyces cerevisiae isolates by a genotypic method JOURNAL OF CLINICAL MICROBIOLOGY McCullough, M. J., Clemons, K. V., FARINA, C., McCusker, J. H., Stevens, D. A. 1998; 36 (2): 557-562

    Abstract

    Saccharomyces cerevisiae is a ubiquitous, ascomycetous yeast, and vaginitis caused by this organism has been reported only very rarely. The aim of the present investigation was to assess the epidemiological relatedness of a group of vaginal and commercial S. cerevisiae isolates by a previously reported genetic typing method, which divided the isolates into two broad groups with numerous subtypes. Nineteen S. cerevisiae isolates obtained from patients suffering from vaginitis and four isolates from commercial products in the same city were analyzed. The cellular DNA from each isolate was digested with the restriction endonuclease EcoRI, and restriction fragment length polymorphisms were generated by horizontal gel electrophoresis. The results showed that although vaginal isolates did not cluster in any particular genetic subtype, multiple patients were infected with indistinguishable strains (there were nine distinct strains among 23 isolates). For two of three patients, all three with two episodes of S. cerevisiae vaginitis, different strains were isolated during the recurrence of this disease. Three other patients with indistinguishable isolates were epidemiologically related in that two were practitioners in the same clinic and the third was a patient at this clinic. We also found that one commercial strain was indistinguishable from the strain isolated from three different women at the time that they were suffering from vaginitis. The findings of the present study suggest that some S. cerevisiae strains may possess properties permitting persistence in the human host. Furthermore, person-to-person contact and the proliferation of the use of S. cerevisiae as a health-food product, in home baking, and in home brewing may be a contributing factor in human colonization and infection with this organism.

    View details for Web of Science ID 000071515100041

    View details for PubMedID 9466776

  • Safety evaluation of chronic fluconazole therapy CHEMOTHERAPY Stevens, D. A., Diaz, M., Negroni, R., MONTEROGEI, F., Castro, L. G., Sampaio, S. A., Borelli, D., Restrepo, A., Franco, L., BRAN, J. L., Arathoon, E. G. 1997; 43 (5): 371-377

    Abstract

    The possible adverse effects of chronic, high-dose fluconazole therapy are detailed from analysis of a multicenter, dose-escalating study of the therapy of invasive mycoses. Ninety-three adult patients were studied, 48 of these received > or = 6 months therapy and 20 received > or = 1 year. Fifty-eight patients received > or = 300 mg/day, and 7 received > or = 600 mg/day. One patient received 1,997 g over 86 months. Twenty-seven percent experienced possible symptomatic side effects, which resulted in 2 patients discontinuing therapy, and 42% had asymptomatic laboratory abnormalities, none of which were progressive. Headache, hair loss and anorexia were the most common symptoms experienced (each by 3% of patients), and eosinophilia and aspartate aminotransferase increases were the most common laboratory findings (12 and 10%, respectively). Fluconazole appears well tolerated and safe in these doses and durations.

    View details for Web of Science ID A1997XT59500011

    View details for PubMedID 9309372

  • Application of DNA typing methods and genetic analysis to epidemiology and taxonomy of Saccharomyces isolates JOURNAL OF CLINICAL MICROBIOLOGY Clemons, K. V., Park, P. S., McCusker, J. H., McCullough, M. J., Davis, R. W., Stevens, D. A. 1997; 35 (7): 1822-1828

    Abstract

    We have previously described differences in phenotype and virulence among clinical and nonclinical isolates of Saccharomyces. To further characterize these isolates, a comparison of restriction fragment length polymorphism (RFLP) patterns and genetic analysis were done. The cellular DNA of each of 49 clinical and 11 nonclinical isolates of Saccharomyces was digested with the endonuclease EcoRI, and the resultant fragments were separated by electrophoresis. Sixty isolates were grouped on the basis of the presence (group B) or absence (group A) of a 3-kb band. Group A contained 43 isolates (35 clinical and 8 nonclinical isolates) in 31 discernible subgroups, and group B had 17 isolates (14 clinical and 3 nonclinical isolates) in 10 subgroups. Interestingly, six of eight known vaginal isolates were group B, with four of those six being identical. Virulence of isolates was associated with membership in group A (P = 0.03). Comparison of known members of sibling species within the genus Saccharomyces, which cannot be distinguished by standard biochemical tests, showed that S. paradoxus, S. bayanus, and S. cerevisiae could be differentiated by RFLP analysis. Genetic analysis of the isolates forming viable spores showed that most group A isolates were diploid and members of the species S. cerevisiae. Those group A and B isolates unable to form viable spores may be diploid hybrids between Saccharomyces species. The group B isolates that formed viable spores were tetraploid and may also be interspecific hybrids. Overall, clinical isolates of Saccharomyces were very heterogeneous and exhibited little clonality. RFLP pattern analysis could be a useful method of demonstrating transmission in patients with infection or between environmental sources and patients.

    View details for Web of Science ID A1997XE59100036

    View details for PubMedID 9196202

  • Therapy for opportunistic fungal infections: past, present and future. Indian journal of cancer Stevens, D. A. 1995; 32 (1): 1-9

    Abstract

    The field of antifungal chemotherapy is presently rapidly moving. It began in 1903, with the successful use of potassium iodide (KI). Then there was little progress for 50 years, when in 1951, nystatin was introduced, the first useful polyene. Four years later amphotericin B followed, which is still the historical standard against which new systemic antifungals are compared. Except for the development of flucytosine, there was little progress until the early 1970s and the development of the azole drugs. The present era, which is characterized largely by the modifications of azole drugs, began with ketoconazole and brought agents which can be given orally and have increasing potency, decreasing toxicity and a broader spectrum of activity. Recent studies have examined ways to ameliorate the well-known toxicities of amphotericin B. A new approach has been to complex the drug with lipids or entrap it in liposomes. Itraconazole is a broad-spectrum oral triazole whose greatest advantages over the imidazoles are in its activity against aspergillosis and cryptococcosis, though it is also efficacious against the endemic deep mycoses. Fluconazole is a broad-spectrum triazole. It has been shown to be efficacious in various forms of superficial candidosis, including esophageal disease. We have shown in a randomized, double-blind, placebo-controlled study that maintenance therapy can completely prevent thrush in AIDS patients with recurrent thrush and possibly prevent all deep and superficial mycoses. Other studies have shown efficacy in cryptococcal meningitis in AIDS comparable to conventional therapy and with far less toxicity, and also in prevention of relapse of cryptococcal disease. Early diagnosis of fungal infections in cancer patients is problematic.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for PubMedID 7558104

  • PATHOGENICITY OF SACCHAROMYCES-CEREVISIAE IN COMPLEMENT FACTOR-5 DEFICIENT MICE INFECTION AND IMMUNITY Byron, J. K., Clemons, K. V., McCusker, J. H., Davis, R. W., Stevens, D. A. 1995; 63 (2): 478-485

    Abstract

    We have previously determined the relative virulence of isolates of Saccharomyces cerevisiae on the basis of differences in proliferation and resistance to clearance in CD-1 mice. These infections were not fatal. To further characterize S. cerevisiae pathogenesis, we studied a virulent clinical isolate, YJM128, and an avirulent nonclinical isolate, Y55, in C5-deficient mice. DBA/2N mice were infected intravenously with YJM128 or Y55, and temporal burdens of yeast cells in various organs were determined. After infection with 10(7) CFU, Y55 increased by 13-fold and YJM128 increased by 20-fold in the brain from day 0 to 3. In addition, YJM128 increased by 4-fold in the kidneys, whereas Y55 decreased by 16-fold. Both isolates declined in number in other organs. In all studies, 90% of mice infected with 10(7) CFU of YJM128 died between days 2 and 7, whereas no mice infected with equivalent numbers of Y55 died. No mice died after infection with 10(6) CFU of Y55 or YJM128. The importance of C5 was confirmed by studies using B10.D2/oSnJ (C5-) mice and their congenic C5+ counterparts. Again, the C5- mice were most susceptible to infection with S. cerevisiae, with 63% infected with YJM128 dying by day 7; no C5+ mice died. No Y55-infected mice died, and mean burdens in the brain at day 14 were sevenfold lower in C5+ mice than in C5- mice. Seven of 10 other S. cerevisiae isolates were also more virulent in DBA/2N than CD-1 mice, causing > or = 40% mortality. These data indicate that C5 is a critical factor in host resistance against S. cerevisiae infections and further confirm the pathogenic potential of some isolates of S. cerevisiae.

    View details for Web of Science ID A1995QC60300016

    View details for PubMedID 7822013

  • SACCHAROMYCES-CEREVISIAE VIRULENCE PHENOTYPE AS DETERMINED WITH CD-1 MICE IS ASSOCIATED WITH THE ABILITY TO GROW AT 42-DEGREES-C AND FORM PSEUDOHYPHAE INFECTION AND IMMUNITY McCusker, J. H., Clemons, K. V., Stevens, D. A., Davis, R. W. 1994; 62 (12): 5447-5455

    Abstract

    Saccharomyces cerevisiae isolates have been shown previously to exhibit a high degree of variation in their ability to proliferate and persist in CD-1 mice (K.V. Clemons, J.H. McCusker, R. W. Davis, and D.A. Stevens, J. Infect. Dis. 169:859-867, 1994). Isolate origin was not a firm predictor of virulence phenotype, since the virulence phenotypes of clinical and nonclinical isolates ranged from virulent to avirulent and from intermediate to avirulent, respectively. Therefore, it was important to determine if there was any association between putative virulence traits and virulence that might help explain the variation in virulence phenotypes. S. cerevisiae isolates spanning a range of virulence phenotypes in experimental infections were examined for putative virulence traits: the ability to grow at supraoptimal temperatures (42, 39, and 37 degrees C), gelatin liquefaction, casein utilization, and pseudohyphal formation. Gelatin liquefaction appeared to be unrelated to pseudohyphal formation on casein or to virulence. Significant differences in the ability to grow at 39 and 42 degrees C were observed when the virulent and intermediate classes were compared with the avirulent class. Less extreme but still significant differences in pseudohyphal formation were observed when the virulent and intermediate classes were compared with the avirulent class. Therefore, two virulence traits, similar to those identified in other pathogenic fungi, the ability to grow at elevated temperatures and pseudohyphal formation, have been identified in S. cerevisiae.

    View details for Web of Science ID A1994PT32900033

    View details for PubMedID 7960125

  • PULMONARY MUCORMYCOSIS PRESENTING AS AN ENDOBRONCHIAL LESION CHEST HUSARI, A. W., Jensen, W. A., Kirsch, C. M., Campagna, A. C., Kagawa, F. T., Hamed, K. A., AZZI, R. L., Stevens, D. A. 1994; 106 (6): 1889-1891

    Abstract

    A 56-year-old diabetic man presented with left upper lobe collapse and postobstructive pneumonitis. Fiberoptic bronchoscopy revealed an endobronchial mass obstructing the left mainstem bronchus. The lesion resembled a bronchial adenoma; however, cytologic and histologic examination revealed invasive mucormycosis. The patient was treated with intravenous amphotericin B followed by endoscopic laser surgery that relieved the obstruction.

    View details for Web of Science ID A1994PX25900046

    View details for PubMedID 7988219

  • GENETIC-CHARACTERIZATION OF PATHOGENIC SACCHAROMYCES-CEREVISIAE ISOLATES GENETICS McCusker, J. H., Clemons, K. V., Stevens, D. A., Davis, R. W. 1994; 136 (4): 1261-1269

    Abstract

    Saccharomyces cerevisiae isolates from human patients have been genetically analyzed. Some of the characteristics of these isolates are very different from laboratory and industrial strains of S. cerevisiae and, for this reason, stringent genetic tests have been used to confirm their identity as S. cerevisiae. Most of these clinical isolates are able to grow at 42 degrees, a temperature that completely inhibits the growth of most other S. cerevisiae strains. This property can be considered a virulence trait and may help explain the presence of these isolates in human hosts. The ability to grow at 42 degrees is shown to be polygenic with primarily additive effects between loci. S. cerevisiae will be a useful model for the evolution and genetic analysis of fungal virulence and the study of polygenic traits.

    View details for Web of Science ID A1994NB82100004

    View details for PubMedID 8013903

  • CONTROL OF INVASIVE PULMONARY ASPERGILLOSIS WITH ORAL ITRACONAZOLE IN A BONE-MARROW TRANSPLANT PATIENT JOURNAL OF INFECTION Denning, D. W., Stepan, D. E., Blume, K. G., Stevens, D. A. 1992; 24 (1): 73-?

    Abstract

    Pulmonary aspergillosis following bone marrow transplantation carries a mortality of 94%, irrespective of current treatment. We treated a patient who had acquired aspergillosis some 80 days after allogeneic bone marrow transplantation, with oral itraconazole, 600 mg daily. After initial deterioration, clinical and radiographic resolution occurred during 3 months of therapy despite severe graft-vs.-host and cytomegalovirus disease. Itraconazole should be considered for therapy of pulmonary aspergillosis in this and other immunocompromised settings.

    View details for Web of Science ID A1992HA14300012

    View details for PubMedID 1312563

  • ULCERATIVE TRACHEOBRONCHITIS AFTER LUNG TRANSPLANTATION - A NEW FORM OF INVASIVE ASPERGILLOSIS AMERICAN REVIEW OF RESPIRATORY DISEASE Kramer, M. R., Denning, D. W., Marshall, S. E., Ross, D. J., Berry, G., LEWISTON, N. J., Stevens, D. A., Theodore, J. 1991; 144 (3): 552-556

    Abstract

    Invasive aspergillosis is frequently a fatal disease in the setting of immunosuppression, including organ transplant recipients. The fungus usually affects lung parenchyma and may disseminate from there. We have recently noted tracheobronchitis in six patients with heart-lung and lung transplants, three of whom had deep mucosal ulceration and histologic evidence of invasive aspergillosis. This apparently new form of invasive disease is initially limited to the anastomosis site and large airways. Ulceration, necrosis, cartilage invasion, and formation of a pseudomembrane are the pathologic features. In two patients subsequent disseminated aspergillosis occurred with a fatal outcome. In the two single-lung recipients, disease was limited to the transplanted side emphasizing the importance of abnormal local defense mechanisms in the airways of lung transplant recipients. Routine bronchoscopic examination of the airways is important in early detection of this complication. Oral therapy with the new, antifungal agent itraconazole was successful in five of the six patients, with fatal relapse in one. A classification of the various forms of saprophytic, allergic, and invasive forms of aspergillus tracheobronchitis, to include this new entity, is proposed.

    View details for Web of Science ID A1991GF55100015

    View details for PubMedID 1654038

  • ENDOCARDITIS DUE TO TRICHOSPORON-BEIGELII - INVITRO SUSCEPTIBILITY OF ISOLATES AND REVIEW REVIEWS OF INFECTIOUS DISEASES Keay, S., Denning, D. W., Stevens, D. A. 1991; 13 (3): 383-386

    Abstract

    Infection with Trichosporon beigelii is an uncommon cause of endocarditis. Of the eight cases of T. beigelii endocarditis that have been reported (one herein and seven previously), six involved prosthetic heart valves and two involved native heart valves. The clinical manifestations of this infection included embolization of the superficial femoral artery or of the bifurcation of the posterior tibial and peroneal arteries in three of these patients (two with prosthetic valve and one with native valve endocarditis). In seven of the eight reported cases, blood cultures were positive for the organism. Although clinical isolates of the organism are generally reported to be susceptible to amphotericin B, isolates can vary in their sensitivities to antifungal agents in vitro depending on the methodology used, and clinical response to therapy with antifungal agents in a regimen that includes amphotericin B is generally poor. Only two of six patients who were treated with antifungal agents survived endocarditis caused by T. beigelii and were apparently cured; one of these patients was also managed surgically with valve replacement. Infection with T. beigelii should be considered in the differential diagnosis of endocarditis in immunocompetent patients, particularly those who have a prosthetic heart valve. Rapid, aggressive therapy may be necessary to eradicate this organism.

    View details for Web of Science ID A1991FM82600006

    View details for PubMedID 1866540

  • CYCLOSPORINE AND ITRACONAZOLE INTERACTION IN HEART AND LUNG-TRANSPLANT RECIPIENTS ANNALS OF INTERNAL MEDICINE Kramer, M. R., Marshall, S. E., Denning, D. W., Keogh, A. M., Tucker, R. M., Galgiani, J. N., LEWISTON, N. J., Stevens, D. A., Theodore, J. 1990; 113 (4): 327-329

    View details for Web of Science ID A1990DU08100013

    View details for PubMedID 2165371

  • New drugs for systemic fungal infections. BMJ (Clinical research ed.) Denning, D. W., Stevens, D. A. 1989; 299 (6696): 407-408

    View details for PubMedID 2506994

  • STEROID-METABOLISM AS A MECHANISM OF ESCAPE FROM PROGESTERONE-MEDIATED GROWTH-INHIBITION IN TRICHOPHYTON-MENTAGROPHYTES JOURNAL OF BIOLOGICAL CHEMISTRY Clemons, K. V., Stover, E. P., Schar, G., STATHIS, P. A., Chan, K., Tokes, L., Stevens, D. A., Feldman, D. 1989; 264 (19): 11186-11192

    Abstract

    It has been shown by us and others that progesterone inhibits the growth of Trichophyton mentagrophytes and that the organism escapes from this inhibition over time. We report here studies which show that escape from growth inhibition is related to the enzymatic transformation of progesterone to polar metabolites. Isolation and identification of the progesterone metabolites confirm the production of 15 alpha-hydroxyprogesterone. In addition, three other metabolites were isolated. Two of these were determined to be 1-dehydroprogesterone and 11 alpha-hydroxyprogesterone. The third metabolite was a 1-dehydro-hydroxyprogesterone, but the location of the hydroxyl group could not be determined unequivocally. Studies using authentic 15 alpha-hydroxyprogesterone, 1-dehydroprogesterone, and 11 alpha-hydroxyprogesterone reveal that these derivatives are significantly less inhibitory to the growth of T. mentagrophytes than progesterone. Pretreatment of organisms with progesterone augments the rate of metabolism and enhances escape. We have described previously a progesterone-binding protein (PBP) in cytoplasmic extracts of T. mentagrophytes and hypothesized that progesterone mediates growth inhibition by binding to the PBP of this organism. The relative binding affinity that progesterone and its metabolites display for PBP correlates with the relative growth inhibitory potency of these compounds. These results suggest that metabolism of progesterone to more polar and less inhibitory compounds, which exhibit lower affinity for PBP, is the mechanism of escape from progesterone-mediated inhibition of growth in this organism.

    View details for Web of Science ID A1989AC81700042

    View details for PubMedID 2738064

  • THE NEW GENERATION OF ANTIFUNGAL DRUGS EUROPEAN JOURNAL OF CLINICAL MICROBIOLOGY & INFECTIOUS DISEASES Stevens, D. A. 1988; 7 (6): 732-735

    View details for Web of Science ID A1988R546000003

    View details for PubMedID 2850912

  • DERMATOPHYTE-HORMONE RELATIONSHIPS - CHARACTERIZATION OF PROGESTERONE-BINDING SPECIFICITY AND GROWTH-INHIBITION IN THE GENERA TRICHOPHYTON AND MICROSPORUM JOURNAL OF CLINICAL MICROBIOLOGY Clemons, K. V., Schar, G., Stover, E. P., Feldman, D., Stevens, D. A. 1988; 26 (10): 2110-2115

    Abstract

    We reported previously that Trichophyton mentagrophytes contains a cytoplasmic macromolecule which specifically binds progesterone. Progesterone is also an effective inhibitor of growth of the fungus. We report here studies which characterize more fully the specific binding properties and the functional responses of T. mentagrophytes and taxonomically related fungi to a series of mammalian steroid hormones. Scatchard analysis of [3H]progesterone binding in both the + and - mating types of Arthroderma benhamiae and in Microsporum canis revealed a single class of binding sites with approximately the same affinity as that in T. mentagrophytes (Kd, 1 X 10(-7) to 2 X 10(-7) M). Trichophyton rubrum had a protein with a higher binding affinity (Kd, 1.6 X 10(-8) M). Characterization of the [3H]progesterone-binding sites in T. mentagrophytes showed the binder to be a protein which was destroyed by trypsin and heating to 56 degrees C. Previous examination of the steroid-binding specificity in T. mentagrophytes had demonstrated that deoxycorticosterone (DOC) and dihydrotestosterone (DHT) were effective competitors for [3H]progesterone binding. Expansion of this study to include other competitors revealed that R5020 (a synthetic progestin), androstenedione, and dehydroepiandosterone possessed relative binding affinities which were 20, 11, and 9% of that of progesterone, respectively. Other ligands tested were less effective. Competition studies for the binder in M. canis resulted in similar findings: DOC and DHT were effective competitors for [3H]progesterone binding. The growth of A. benhamiae + and -, M. canis, and T. rubrum were all inhibited by progesterone in a dose-responsive manner, with 50% inhibition achieved at concentrations of 9.8 x 10(-6), 1.2 x 10(-5), 1.5 x 10(-5), and 2.7 x 10(-6) M. respectively,.

    View details for Web of Science ID A1988Q160000035

    View details for PubMedID 3182998

  • CLINICAL AND MICROBIOLOGICAL FEATURES OF INFECTION WITH MALASSEZIA-PACHYDERMATIS IN HIGH-RISK INFANTS JOURNAL OF INFECTIOUS DISEASES Mickelsen, P. A., VIANOPAULSON, M. C., Stevens, D. A., Diaz, P. S. 1988; 157 (6): 1163-1168

    Abstract

    Malassezia pachydermatis, a yeast that has not previously been implicated as a cause of human disease, was isolated from cultures of blood from three infants. All infants were 25-27 w of gestational age and had multiple underlying medical problems. The infants had been hospitalized for at least six weeks, had received broad-spectrum antibiotics, and had received parenteral lipid nutrition via a central venous catheter. In one patient, fungemia was accompanied by clinical and laboratory evidence of Broviac catheter infection. During a three-year period, M. pachydermatis was also recovered from fungal cultures of an additional 30 patients, 85% of whom were infants. A pathogenic role for M. pachydermatis recovered from sources other than blood or catheters was not established. Risk factors for and symptoms in infants with M. pachydermatis fungemia appeared to be similar to those described for Malassezia furfur sepsis.

    View details for Web of Science ID A1988N738500008

    View details for PubMedID 3373021

  • PHARMACOLOGY AND TOXICITY OF HIGH-DOSE KETOCONAZOLE ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Sugar, A. M., ALSIP, S. G., Galgiani, J. N., Graybill, J. R., Dismukes, W. E., Cloud, G. A., CRAVEN, P. C., Stevens, D. A. 1987; 31 (12): 1874-1878

    Abstract

    One hundred sixty patients were entered in two multicenter protocols to receive 400 to 2,000 mg of ketoconazole once daily for nonmeningeal or meningeal coccidiodomycosis. For 24 h after administration of all doses, mean concentrations in serum exceeded MICs for Coccidioides immitis (trough concentrations, greater than 1 microgram/ml). Mean peak concentrations occurred 4 to 6 h after administration, ranging from 7 to 17 micrograms/ml for doses of 400 to 2,000 mg. Incremental increases in peak concentrations in serum were greatest at doses of less than or equal to 1,200 mg. To investigate whether long-term therapy altered concentrations in serum, serial data were studied by several methods. The results suggested a trend to increased levels in serum with prolonged therapy, but were not statistically significant. All 168 cerebrospinal fluid (CSF) samples from meningitis patients contained less than or equal to 2.9 micrograms/ml, and only 6 contained greater than 1 microgram/ml. There was no apparent relation between dose, time after dose, site of CSF sampling, or concurrent inflammation and CSF ketoconazole concentration. Neither concentration in serum, toxicity, nor outcome correlated with dose, calculated in milligrams per kilogram at the fixed doses (400-mg increments) under study. Likewise, at the various doses, concentration in serum did not correlate with outcome or toxicity, suggesting that individual drug disposition was not an important factor in outcome or toxicity. Toxicity was reversible, and principal side effects were nausea and vomiting (50%), gynecomastia (21%), decreased libido (13%), alopecia (8%), elevated liver function tests (5%), pruritus (5%), and rash (4%). Gastrointestinal and endocrinologic toxicity were dose related and increased at doses greater than 800 mg. The cumulative percent toxicity requiring discontinuation of drug was 6, 17, 23, and 56% at 400-, 800-, 1,200-, and 1,600-mg doses. Doses of >400 mg are thus markedly more toxic, and efficacy data for nonmeningeal disease have not demonstrated that they are more efficacious.

    View details for Web of Science ID A1987L150800003

    View details for PubMedID 3326525

  • MICONAZOLE IN COCCIDIOIDOMYCOSIS WESTERN JOURNAL OF MEDICINE Stevens, D. A. 1977; 126 (4): 315-316

    View details for Web of Science ID A1977DC47300023

    View details for PubMedID 18747924

  • MICONAZOLE WESTERN JOURNAL OF MEDICINE Stevens, D. A. 1977; 126 (6): 510-510

    View details for Web of Science ID A1977DK44100032

    View details for PubMedID 18747972

  • DOES EB VIRUS CAUSE MENINGITIS OR ENCEPHALITIS - RESULTS OF A SURVEY - CASE REPORT DISEASES OF THE NERVOUS SYSTEM Stevens, D. A. 1974; 35 (1): 13-16

    View details for Web of Science ID A1974R882300002

    View details for PubMedID 17894049

Conference Proceedings


  • Developing a vaccine against aspergillosis Stevens, D. A., Clemons, K. V., Liu, M. INFORMA HEALTHCARE. 2011: S170-S176

    Abstract

    Although there is considerable experimental data to support the idea, bringing a fungal vaccine to fruition has been elusive. Moreover, vaccinating the immunocompromised, susceptible to an opportunistic disease such as invasive aspergillosis, seems formidable. However, pioneering studies using Aspergillus particulate forms or homogenates, and recently, recombinant proteins, have demonstrated feasibility. Moreover, T cell receptors also recognize glycotopes if presented in the appropriate MHC-binding context. The potential role of induced antibody has been appreciated only recently. Recent studies in our laboratory with heat-killed Saccharomyces (HKY) have raised the possibility of development of a panfungal vaccine. This yeast may be nature's experimental reagent, to show the way to a protective protein-carbohydrate conjugate vaccine. Subcutaneous HKY is an effective vaccine against Aspergillus, Coccidioides or Candida challenge. We have learned the protective moiety is in the cell wall, and proteins, glucan and lipid all seem important. We have also found the cell wall glycans alone, mannan or glucan, as a vaccine each provide significant protection. This leads to consideration of the importance of glycosylated proteins and glycan polymer-protein conjugates in vaccine development. We think the most productive route to a fungal-specific vaccine may be a conjugate vaccine that combines the optimally configured glycan with a specific immunogenic protein. Our work so far suggests that some proteins may be sufficiently cross-immunogenic, such that combined with the appropriate glycan, it may be possible to develop a pan-fungal vaccine.

    View details for DOI 10.3109/13693786.2010.497775

    View details for Web of Science ID 000288327000026

    View details for PubMedID 20608783

  • Third Advances Against Aspergillosis Meeting 2008. Stevens, D. A., Clemons, K. V. 2008: 851-853

    Abstract

    On 16-19 January 2008, the Third Advances Against Aspergillosis Meeting took place in Miami Beach, FL, USA. There were 351 registrants from 26 countries. The two earlier meetings had taken place in San Francisco, CA, 2004 and in Athens, Greece, 2006, and the series has become the place for scientists and clinicians to be updated on developments relevant to all aspects of this fungal genus.

    View details for DOI 10.1586/14787210.6.6.851

    View details for PubMedID 19053897

  • Advances against aspergillosis (September 9-11, 2004, San Francisco, California). Clemons, K. V., Steinbach, W. J., Denning, D. W., Stevens, D. A. 2005: 315-317

    View details for PubMedID 15770459

  • Diagnosis of fungal infections: current status Stevens, D. A. OXFORD UNIV PRESS. 2002: 11-19

    Abstract

    Diagnosing infections remains a problem in the management of fungal diseases, particularly in the immunocompromised host. Signs and symptoms are non-specific, colonization is difficult to distinguish from invasive disease, blood cultures are commonly negative and patients are often unable to undergo invasive diagnostic procedures. This situation has led to the strategy of initiating empirical therapy in the high-risk patient. A variety of tests has been applied to several body fluids. At the simplest level, the clinician must be familiar with the appearance of various fungi in tissue. Non-culture methods include antibody- and antigen-based assays, metabolite detection and molecular identification. The latter includes PCR identification of fungal DNA from body fluid samples using conserved or specific genome sequences. Detection of glucan in blood has been achieved using crab amoebocyte lysate. With aspergillosis, predictive clinical correlates have been defined, respiratory tract cultures are highly predictive of invasive disease in the appropriate setting and certain CT scan findings enable early diagnosis. Bronchoalveolar lavage is also very useful. Galactomannan antigen testing of blood is routine in some European centres, with EIA methodology supplanting agglutination because of apparently greater sensitivity. PCR has been made specific by genus-specific probes, with 100% sensitivity and reasonable specificity. In candidosis, the number of sites of colonization correlates with invasion. Tests for mannan antibodies and antigenaemia are currently of interest. Metabolite assays appeared promising but have not been pursued commercially. In cryptococcosis, pronase treatment of serum has reduced false positives and false negatives, and improved reproducibility of titres. Birdseed agar improves culture specificity. In coccidioidomycosis, serology is the exemplar for all mycology. Gene probes have accelerated diagnosis by culture. In histoplasmosis, the antigenuria test's high sensitivity and specificity has dispelled the chronic confusion in interpreting antibody test results.

    View details for Web of Science ID 000174028600005

    View details for PubMedID 11801576

  • A randomized trial of itraconazole in allergic bronchopulmonary aspergillosis. Stevens, D. A., Schwartz, H. J., Lee, J. Y., Moskovitz, B. L., Jerome, D. C., Catanzaro, A., Bamberger, D. M., Weinmann, A. J., TUAZON, C. U., Judson, M. A., Platts-Mills, T. A., DeGraff, A. C., Grossman, J., Slavin, R. G., Reuman, P. MASSACHUSETTS MEDICAL SOC. 2000: 756-762

    Abstract

    Allergic bronchopulmonary aspergillosis is a hypersensitivity disorder that can progress from an acute phase to chronic disease. The main treatment is systemic corticosteroids, but data from uncontrolled studies suggest that itraconazole, an orally administered antifungal agent, may be an effective adjunctive therapy.We conducted a randomized, double-blind trial of treatment with either 200 mg of itraconazole twice daily or placebo for 16 weeks in patients who met immunologic and pulmonary-function criteria for corticosteroid-dependent allergic bronchopulmonary aspergillosis. A response was defined as a reduction of at least 50 percent in the corticosteroid dose, a decrease of at least 25 percent in the serum IgE concentration, and one of the following: an improvement of at least 25 percent in exercise tolerance or pulmonary-function tests or resolution or absence of pulmonary infiltrates. In a second, open-label part of the trial, all the patients received 200 mg of itraconazole per day for 16 weeks.There were responses in 13 of 28 patients in the itraconazole group (46 percent), as compared with 5 of 27 patients in the placebo group (19 percent, P=0.04). The rate of adverse events was similar in the two groups. In the subsequent open-label phase, 12 of the 33 patients who had not had a response during the double-blind phase (36 percent) had responses, and none of the patients who had a response in the double-blind phase of the trial had a relapse.For patients with corticosteroid-dependent allergic bronchopulmonary aspergillosis, the addition of itraconazole can lead to improvement in the condition without added toxicity.

    View details for Web of Science ID 000085846900002

    View details for PubMedID 10717010

  • Combined treatment: antifungal drugs with antibodies, cytokines or drugs Stevens, D. A., Kullberg, B. J., Brummer, E., Casadevall, A., Netea, M. G., Sugar, A. M. INFORMA HEALTHCARE. 2000: 305-315

    Abstract

    To improve present results with antifungal drugs, modulation of the host immune response is being explored. Human phagocytes of various lineages work cooperatively in vitro with antifungal drugs to inhibit or kill fungal pathogens, and this activity is augmented by several recombinant cytokines. Monoclonal antibodies against the cryptococcal capsule have been shown to act as an adjunct in enhancing the outcome of cryptococcosis in animal models. This approach is now being pursued in systematic clinical trials. In experimental candidiasis, several manipulations of the immune system, via administration of cytokines, gene deletion or antibodies to cytokines, have been shown to significantly affect survival and fungal clearance in vivo. This approach has already been demonstrated to be of benefit with recombinant human granulocyte-colony stimulating factor adjunct therapy of human candidiasis. Combining antifungal drugs of different classes may enhance their therapeutic effect.

    View details for Web of Science ID 000166958800032

    View details for PubMedID 11204158

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