Ellen Jo Baron

All Publications

Streptococcus agalactiae strains with chromosomal deletions evade detection with molecular methods. Journal of clinical microbiology Tickler, I. A., Tenover, F. C., Dewell, S., Le, V. M., Blackman, R. N., Goering, R. V., Rogers, A. E., Piwonka, H., Jung-Hynes, B. D., Chen, D. J., Loeffelholz, M. J., Gnanashanmugam, D., Baron, E. J. 2019
Abstract

Surveillance of circulating microbial populations is critical for monitoring the performance of a molecular diagnostic test. In this study, we characterized 31 isolates of Streptococcus agalactiae (Group B Streptococcus, GBS) from several geographic locations in the United States and Ireland that contain deletions in or adjacent to the region of the chromosome that encodes the hemolysin gene cfb, the region targeted by the Xpert GBS and GBS LB assays. PCR-negative, culture-positive isolates were recognized during verification studies of the Xpert GBS assay in 12 laboratories between 2012 and 2018. Whole genome sequencing of 15 GBS isolates from 11 laboratories revealed four unique deletions of chromosomal DNA ranging from 181 base pairs to 49 kilobases. Prospective surveillance studies demonstrated that the prevalence of GBS isolates containing deletions in the convenience sample was <1% in three geographic locations but 7% in a fourth location. Among the 15 isolates with chromosomal deletions, multiple pulsed-field gel electrophoresis (PFGE) types were identified, one of which appears to be broadly dispersed across the United States.

View details for DOI 10.1128/JCM.02040-18

View details for PubMedID 30760532
Defining System Requirements for Simplified Blood Culture to Enable Widespread Use in Resource-Limited Settings. Diagnostics (Basel, Switzerland) Dailey, P. J., Osborn, J., Ashley, E. A., Baron, E. J., Dance, D. A., Fusco, D., Fanello, C., Manabe, Y. C., Mokomane, M., Newton, P. N., Tessema, B., Isaacs, C., Dittrich, S. 2019; 9 (1)
Abstract

Bacterial blood stream infections (BSI) are a common cause of mortality and morbidity globally. As the causative agents and the resulting treatment decisions vary, near-patient testing and surveillance tools are necessary to monitor bacterial causes and resistance to antimicrobial agents. The gold standard to identify BSIs is blood culture (BC), a methodology not widely available in resource-limited settings. The aim of the study was to map out a target product profile of a simplified BC system (SBCS) to inform product development efforts. To identify the desired characteristics of a SBCS, we enlisted a small group of specialists working in Africa and Asia. Questions were used to understand challenges and how these constraints inform system requirements. The specialists were infectious disease physicians, public health/clinical microbiologists, clinical researchers, and technology experts with different geographical backgrounds. All suggested that BC should ideally be available at the district hospital level. Many of the same operational challenges, such as limited availability of culture bottles, electricity and internet connectivity, profuse dust, the lack of ambient temperature control, and human capacity constraints were identified across the different regions. BCs, although the accepted gold standard for diagnosis of BSIs, are not widely available outside of reference/research centers in Africa and Asia. To extend the reach of this important tool, it is crucial to engage product developers and academic research partners to develop accessible alternatives.

View details for DOI 10.3390/diagnostics9010010

View details for PubMedID 30641976
A Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2013 Recommendations by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM) CLINICAL INFECTIOUS DISEASES Baron, E. J., Miller, J. M., Weinstein, M. P., Richter, S. S., Gilligan, P. H., Thomson, R. B., Bourbeau, P., Carroll, K. C., Kehl, S. C., Dunne, W. M., Robinson-Dunn, B., Schwartzman, J. D., Chapin, K. C., Snyder, J. W., Forbes, B. A., Patel, R., Rosenblatt, J. E., Pritt, B. S. 2013; 57 (4): E22-E121
Abstract

The critical role of the microbiology laboratory in infectious disease diagnosis calls for a close, positive working relationship between the physician and the microbiologists who provide enormous value to the health care team. This document, developed by both laboratory and clinical experts, provides information on which tests are valuable and in which contexts, and on tests that add little or no value for diagnostic decisions. Sections are divided into anatomic systems, including Bloodstream Infections and Infections of the Cardiovascular System, Central Nervous System Infections, Ocular Infections, Soft Tissue Infections of the Head and Neck, Upper Respiratory Infections, Lower Respiratory Tract infections, Infections of the Gastrointestinal Tract, Intraabdominal Infections, Bone and Joint Infections, Urinary Tract Infections, Genital Infections, and Skin and Soft Tissue Infections; or into etiologic agent groups, including Tickborne Infections, Viral Syndromes, and Blood and Tissue Parasite Infections. Each section contains introductory concepts, a summary of key points, and detailed tables that list suspected agents; the most reliable tests to order; the samples (and volumes) to collect in order of preference; specimen transport devices, procedures, times, and temperatures; and detailed notes on specific issues regarding the test methods, such as when tests are likely to require a specialized laboratory or have prolonged turnaround times. There is redundancy among the tables and sections, as many agents and assay choices overlap. The document is intended to serve as a reference to guide physicians in choosing tests that will aid them to diagnose infectious diseases in their patients.

View details for DOI 10.1093/cid/cit278

View details for Web of Science ID 000322342500001

View details for PubMedID 23845951

View details for PubMedCentralID PMC3719886
Analytical Performance Characteristics of the Cepheid GeneXpert Ebola Assay for the Detection of Ebola Virus PLOS ONE Pinsky, B. A., Sahoo, M. K., Sandlund, J., Kleman, M., Kulkarni, M., Grufman, P., Nygren, M., Kwiatkowski, R., Baron, E. J., Tenover, F., Denison, B., Higuchi, R., van Atta, R., Beer, N. R., Carrillo, A. C., Naraghi-Arani, P., Mire, C. E., Ranadheera, C., Grolla, A., Lagerqvist, N., Persing, D. H. 2015; 10 (11)
View details for DOI 10.1371/journal.pone.0142216

View details for Web of Science ID 000364480900020

View details for PubMedID 26562786
A Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2013 Recommendations by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM) CLINICAL INFECTIOUS DISEASES Baron, E. J., Miller, J. M., Weinstein, M. P., Richter, S. S., Gilligan, P. H., Thomson, R. B., Bourbeau, P., Carroll, K. C., Kehl, S. C., Dunne, W. M., Robinson-Dunn, B., Schwartzman, J. D., Chapin, K. C., Snyder, J. W., Forbes, B. A., Patel, R., Rosenblatt, J. E., Pritt, B. S. 2013; 57 (4): 485-488
Abstract

The critical role of the microbiology laboratory in infectious disease diagnosis calls for a close, positive working relationship between the physician and the microbiologists who provide enormous value to the health care team. This document, developed by both laboratory and clinical experts, provides information on which tests are valuable and in which contexts, and on tests that add little or no value for diagnostic decisions. Sections are divided into anatomic systems, including Bloodstream Infections and Infections of the Cardiovascular System, Central Nervous System Infections, Ocular Infections, Soft Tissue Infections of the Head and Neck, Upper Respiratory Infections, Lower Respiratory Tract infections, Infections of the Gastrointestinal Tract, Intraabdominal Infections, Bone and Joint Infections, Urinary Tract Infections, Genital Infections, and Skin and Soft Tissue Infections; or into etiologic agent groups, including Tickborne Infections, Viral Syndromes, and Blood and Tissue Parasite Infections. Each section contains introductory concepts, a summary of key points, and detailed tables that list suspected agents; the most reliable tests to order; the samples (and volumes) to collect in order of preference; specimen transport devices, procedures, times, and temperatures; and detailed notes on specific issues regarding the test methods, such as when tests are likely to require a specialized laboratory or have prolonged turnaround times. There is redundancy among the tables and sections, as many agents and assay choices overlap. The document is intended to serve as a reference to guide physicians in choosing tests that will aid them to diagnose infectious diseases in their patients.

View details for DOI 10.1093/cid/cit441

View details for Web of Science ID 000322342500008

View details for PubMedCentralID PMC3719893
Executive summary: a guide to utilization of the microbiology laboratory for diagnosis of infectious diseases: 2013 recommendations by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM)(a). Clinical infectious diseases Baron, E. J., Miller, J. M., Weinstein, M. P., Richter, S. S., Gilligan, P. H., Thomson, R. B., Bourbeau, P., Carroll, K. C., Kehl, S. C., Dunne, W. M., Robinson-Dunn, B., Schwartzman, J. D., Chapin, K. C., Snyder, J. W., Forbes, B. A., Patel, R., Rosenblatt, J. E., Pritt, B. S. 2013; 57 (4): 485-488
Abstract

The critical role of the microbiology laboratory in infectious disease diagnosis calls for a close, positive working relationship between the physician and the microbiologists who provide enormous value to the health care team. This document, developed by both laboratory and clinical experts, provides information on which tests are valuable and in which contexts, and on tests that add little or no value for diagnostic decisions. Sections are divided into anatomic systems, including Bloodstream Infections and Infections of the Cardiovascular System, Central Nervous System Infections, Ocular Infections, Soft Tissue Infections of the Head and Neck, Upper Respiratory Infections, Lower Respiratory Tract infections, Infections of the Gastrointestinal Tract, Intraabdominal Infections, Bone and Joint Infections, Urinary Tract Infections, Genital Infections, and Skin and Soft Tissue Infections; or into etiologic agent groups, including Tickborne Infections, Viral Syndromes, and Blood and Tissue Parasite Infections. Each section contains introductory concepts, a summary of key points, and detailed tables that list suspected agents; the most reliable tests to order; the samples (and volumes) to collect in order of preference; specimen transport devices, procedures, times, and temperatures; and detailed notes on specific issues regarding the test methods, such as when tests are likely to require a specialized laboratory or have prolonged turnaround times. There is redundancy among the tables and sections, as many agents and assay choices overlap. The document is intended to serve as a reference to guide physicians in choosing tests that will aid them to diagnose infectious diseases in their patients.

View details for DOI 10.1093/cid/cit441

View details for PubMedID 23881727
Trends in incidence and susceptibility among methicillin-resistant Staphylococcus aureus isolated from intranasal cultures associated with rhinosinusitis. American journal of rhinology & allergy Rujanavej, V., Soudry, E., Banaei, N., Baron, E. J., Hwang, P. H., Nayak, J. V. 2013; 27 (2): 134-137
Abstract

Reports regarding the incidence and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) in rhinosinusitis (RS) are limited. This study was designed to identify epidemiology and trends of MRSA incidence and antimicrobial resistance in the sinonasal cavities.This is a retrospective case series. All intranasal/sinus cultures obtained by otolaryngologists at Stanford over a 20-year period (1990-2010) were retrospectively reviewed by mining the microbiology database. Nested searches were then made for all S. aureus and MRSA cultures. Patterns of incidence and changes in antibiotic susceptibilities were tabulated and statistical analysis was performed.Our search retrieved 10,387 positive intranasal culture samples, with S. aureus found in 800 (7.7%), and MRSA comprising 110 (1.06%) of this subset. Between the years of 1990 and 1999, only 2/112 (1.7%) of S. aureus-positive nasal cultures were positive for MRSA, with a sharp rise in incidence to 86/606 (14.2%) from 2000 to 2005, and to 22/82, 26.8% from 2006 to 2010. On a percent basis, using logistic regression modeling, this represents a statistically significant increasing trend (p < 0.0001) for MRSA sinusitis. However, over the 20-year interval studied, the patterns of antibiotic resistance among MRSA remained unaltered, especially with regard to trimethoprim-sulfamethoxazole and vancomycin.S. aureus and MRSA isolates from intranasal cultures, which were essentially absent before the year 2000, became significantly more common earlier this decade. These data show the increased role of MRSA in sinusitis. MRSA antibiotic susceptibilities have remained, however, largely stable during this time period.

View details for DOI 10.2500/ajra.2013.27.3858

View details for PubMedID 23562203
Trends in incidence and susceptibility among methicillin-resistant Staphylococcus aureus isolated from intranasal cultures associated with rhinosinusitis. American journal of rhinology & allergy Rujanavej, V., Soudry, E., Banaei, N., Baron, E. J., Hwang, P. H., Nayak, J. V. 2013; 27 (2): 134-137
Abstract

Reports regarding the incidence and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) in rhinosinusitis (RS) are limited. This study was designed to identify epidemiology and trends of MRSA incidence and antimicrobial resistance in the sinonasal cavities.This is a retrospective case series. All intranasal/sinus cultures obtained by otolaryngologists at Stanford over a 20-year period (1990-2010) were retrospectively reviewed by mining the microbiology database. Nested searches were then made for all S. aureus and MRSA cultures. Patterns of incidence and changes in antibiotic susceptibilities were tabulated and statistical analysis was performed.Our search retrieved 10,387 positive intranasal culture samples, with S. aureus found in 800 (7.7%), and MRSA comprising 110 (1.06%) of this subset. Between the years of 1990 and 1999, only 2/112 (1.7%) of S. aureus-positive nasal cultures were positive for MRSA, with a sharp rise in incidence to 86/606 (14.2%) from 2000 to 2005, and to 22/82, 26.8% from 2006 to 2010. On a percent basis, using logistic regression modeling, this represents a statistically significant increasing trend (p < 0.0001) for MRSA sinusitis. However, over the 20-year interval studied, the patterns of antibiotic resistance among MRSA remained unaltered, especially with regard to trimethoprim-sulfamethoxazole and vancomycin.S. aureus and MRSA isolates from intranasal cultures, which were essentially absent before the year 2000, became significantly more common earlier this decade. These data show the increased role of MRSA in sinusitis. MRSA antibiotic susceptibilities have remained, however, largely stable during this time period.

View details for DOI 10.2500/ajra.2013.27.3858

View details for PubMedID 23562203
Methicillin-resistant Staphylococcus aureus diagnostics: state of the art. Expert opinion on medical diagnostics Baron, E. J., Tenover, F. C. 2012; 6 (6): 585-592
Abstract

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) is among the most common causes of community- and healthcare-acquired infections, accounting for > 80,000 invasive infections in the United States in 2010 according to the Center for Disease Control and Prevention's Active Bacterial Core Surveillance data. Control and treatment of MRSA depend on reliable identification, which is challenging. This article reviews the current status of detection and identification of MRSA. Areas covered: Publications since 2001, guidelines from the Clinical Laboratory Standards Institute and the European Committee on Antimicrobial Susceptibility Testing, common microbiology laboratory practices for identification and characterization of MRSA in human samples, and recent publications that assessed patient care outcomes of various detection and intervention strategies were surveyed for this review. Expert opinion: Given the predilection of Staphylococcus aureus to modify its genetic characteristics, thereby enabling the species to stay one step ahead of laboratory detection systems, phenotypic methods for detection of antibiotic resistance mechanisms, especially those directed against the beta-lactam family, will continue to be required, in some situations, for the foreseeable future. Molecular methods are now the gold standard for surveillance, yielding higher sensitivity than the slower, culture-based methods. The newer molecular surveillance methods for detecting methicillin-resistant S. aureus (MRSA) colonization and for rapid and accurate identification of S. aureus from growth in culture systems have revolutionized patient care, enabling rapid interventions that lead to better individual patient outcomes, such as fewer postsurgical site infections, and better overall institutional infection control (fewer healthcare-associated MRSA infections).

View details for DOI 10.1517/17530059.2012.709233

View details for PubMedID 23480839
Can a Simple Flotation Method Lower the Limit of Detection of Mycobacterium tuberculosis in Extrapulmonary Samples Analyzed by the GeneXpert MTB/RIF Assay? JOURNAL OF CLINICAL MICROBIOLOGY Taylor, N., Gaur, R. L., Baron, E. J., Banaei, N. 2012; 50 (7): 2272-2276
Abstract

The rapid and accurate diagnosis of tuberculosis (TB) in children and extrapulmonary TB in adults continues to be a challenge. In this study, we determined the lower limit of detection (LOD) of the GeneXpert MTB/RIF assay with nonrespiratory specimens and investigated the utility of flotation procedures for concentrating the bacilli. Clinical specimens (9 cerebrospinal fluid [CSF], 13 gastric aspirate, 8 tissue, and 17 stool) were spiked with single-celled Mycobacterium tuberculosis, and the LOD of the GeneXpert assay was determined. Flotation studies were conducted with sucrose and NaCl, and the cycle thresholds of the MTB/RIF assay were compared between treated and untreated samples. There was no significant difference between the LODs of the GeneXpert assay with saline solution (median, 33 CFU/ml) and CSF (median, 25 CFU/ml) (P > 0.05) or gastric aspirate samples (median, 58 CFU/ml) (P > 0.05). The LOD with spiked tissue (median, 1,525 CFU/ml) and stool samples (median, 6,800 CFU/ml) was significantly elevated compared to that determined with saline solution (P ≤ 0.05 and ≤ 0.0005, respectively). Flotation studies with sucrose or NaCl did not consistently result in lowered cycle thresholds in stool or gastric aspirates, but a cycle reduction of >10 was achieved in two of the three pooled CSF samples. Unlike the results seen with tissue and stool samples, there was no significant PCR inhibition in the MTB/RIF assay with CSF and gastric aspirates. Although preconcentration of CSF samples with sucrose and NaCl may enhance detection of M. tuberculosis by PCR, further advances are needed to concentrate the bacilli and eliminate PCR inhibitors in paucibacillary nonrespiratory samples.

View details for DOI 10.1128/JCM.01012-12

View details for Web of Science ID 000307360800017

View details for PubMedID 22553234
Laboratory Diagnosis of Clostridium difficile Infection Can Molecular Amplification Methods Move Us Out of Uncertainty? JOURNAL OF MOLECULAR DIAGNOSTICS Tenover, F. C., Baron, E. J., Peterson, L. R., Persing, D. H. 2011; 13 (6): 573-582
Abstract

The laboratory diagnosis of Clostridium difficile infection (CDI) continues to be challenging. Recent guidelines from professional societies in the United States note that enzyme immunoassays for toxins A and B do not have adequate sensitivity to be used alone for detecting CDI, yet the optimal method for diagnosing this infection remains unclear. Nucleic acid amplification tests (NAATs) that target chromosomal toxin genes (usually the toxin B gene, tcdB) show high sensitivity and specificity, provide rapid results, and are amenable to both batch and on-demand testing, but these tests were not universally recommended for routine use in the recent guidelines. Rather, two-step algorithms that use glutamate dehydrogenase (GDH) assays to screen for C. difficile in stool specimens, followed by either direct cytotoxin testing or culture to identify toxin-producing C. difficile isolates, were recommended in one guideline and either GDH algorithms or NAATs were recommended in another guideline. Unfortunately, neither culture nor direct cytotoxin testing is widely available. In addition, this two-step approach requires 48 to 92 hours to complete, which may delay the initiation of therapy and critical infection control measures. Recent studies also show the sensitivity of several GDH assays to be <90%. This review considers the role of NAATs for diagnosing CDI and explores their potential advantages over two-step algorithms, including shorter time to results, while providing comparable, if not superior, accuracy.

View details for DOI 10.1016/j.jmoldx.2011.06.001

View details for Web of Science ID 000297662400001

View details for PubMedID 21854871
MRSA: a case of pathogens, politics and penalties TRENDS IN MICROBIOLOGY Baron, E. J., Lewis, H. 2011; 19 (4): 153-155
Abstract

In the current era of public scientific 'debate' such as the scientific merit of climate change, it should come as no surprise that a bacterium would have its 15 minutes of political limelight. Furthermore, a few dedicated citizens can truly influence the lives of many by changing the law of the land. For microbiologists, who often complain that our contributions go unnoticed and that we have no political power, this story serves to prove otherwise.

View details for DOI 10.1016/j.tim.2011.01.005

View details for Web of Science ID 000290081600001

View details for PubMedID 21353565
A Biosensor Platform for Rapid Antimicrobial Susceptibility Testing Directly From Clinical Samples JOURNAL OF UROLOGY Mach, K. E., Mohan, R., Baron, E. J., Shih, M., Gau, V., Wong, P. K., Liao, J. C. 2011; 185 (1): 148-153
Abstract

A significant barrier to efficient antibiotic management of infection is that the standard diagnostic methodologies do not provide results at the point of care. The delays between sample collection and bacterial culture and antibiotic susceptibility reporting have led to empirical use of antibiotics, contributing to the emergence of drug resistant pathogens. As a key step toward the development of a point of care device for determining the antibiotic susceptibility of urinary tract pathogens, we report on a biosensor based antimicrobial susceptibility test.For assay development bacteria were cultured with or without antibiotics, and growth was quantitated by determining viable counts and electrochemical biosensor measurement of bacterial 16S rRNA. To determine antibiotic susceptibility directly from patient samples, urine was cultured on antibiotic plates for 2.5 hours and growth was determined by electrochemical measurement of bacterial 16S rRNA. For assay validation 252 urine samples were collected from patients at the Spinal Cord Injury Service at Veterans Affairs Palo Alto Health Care System. The biosensor based antimicrobial susceptibility test was completed for samples containing gram-negative organisms. Pathogen identification and antibiotic susceptibility results were compared between our assay and standard microbiological analysis.A direct biosensor quantitation of bacterial 16S rRNA can be used to monitor bacterial growth for a biosensor based antimicrobial susceptibility test. Clinical validation of a biosensor based antimicrobial susceptibility test with patient urine samples demonstrated that this test was 94% accurate in 368 pathogen-antibiotic tests compared to standard microbiological analysis.This biosensor based antimicrobial susceptibility test, in concert with our previously described pathogen identification assay, can provide culture and susceptibility information directly from a urine sample within 3.5 hours.

View details for DOI 10.1016/j.juro.2010.09.022

View details for Web of Science ID 000285141900047

View details for PubMedID 21074208
Use and Cost-Effectiveness of Intraoperative Acid-Fast Bacilli and Fungal Cultures in Assessing Infection of Joint Arthroplasties JOURNAL OF ARTHROPLASTY Wadey, V. M., Huddleston, J. I., Goodman, S. B., Schurman, D. J., Maloney, W. J., Baron, E. J. 2010; 25 (8): 1231-1234
Abstract

The objective of this study is to determine a protocol for collecting acid-fast bacilli (AFB) and fungal intraoperative cultures during orthopedic procedures. An observational study was undertaken. Four hundred forty-six AFB cultures and 486 fungal cultures were processed over a 2-year period. The number of positive cultures was determined. A protocol specific to handling these types of specimens was developed. Cost analysis was completed to determine both the time and money saved if the new protocol was implemented. The infrequency of positive AFB and fungal cultures in this study suggests that it is only necessary to routinely request AFB and fungal cultures on 1 of 5 samples. Implementation of this protocol has potential to lead to substantial cost reduction and resource savings without diminishing patient outcomes.

View details for DOI 10.1016/j.arth.2009.08.018

View details for Web of Science ID 000284749500009

View details for PubMedID 19879728
Impact of Strain Type on Detection of Toxigenic Clostridium difficile: Comparison of Molecular Diagnostic and Enzyme Immunoassay Approaches JOURNAL OF CLINICAL MICROBIOLOGY Tenover, F. C., Novak-Weekley, S., Woods, C. W., Peterson, L. R., Davis, T., Schreckenberger, P., Fang, F. C., Dascal, A., Gerding, D. N., Nomura, J. H., Goering, R. V., Akerlund, T., Weissfeld, A. S., Baron, E. J., Wong, E., Marlowe, E. M., Whitmore, J., Persing, D. H. 2010; 48 (10): 3719-3724
Abstract

A multicenter clinical trial assessed the performance of the Cepheid Xpert C. difficile assay on stool specimens collected from patients suspected of having Clostridium difficile infection (CDI). A total of 2,296 unformed stool specimens, collected from seven study sites, were tested by Xpert C. difficile enrichment culture followed by cell culture cytotoxicity testing of the isolates (i.e., toxigenic culture with enrichment) and the study sites' standard C. difficile test methods. The methods included enzyme immunoassay (EIA), direct cytotoxin testing, and two- and three-step algorithms using glutamate dehydrogenase (GDH) screening followed by either EIA or EIA and an in-house PCR assay. All C. difficile strains were typed by PCR-ribotyping. Compared to results for toxigenic culture with enrichment, the sensitivity, specificity, and positive and negative predictive values of the Xpert assay were 93.5, 94.0, 73.0, and 98.8%, respectively. The overall sensitivity of the EIAs compared to that of enrichment culture was 60.0%, and the sensitivity of combined GDH algorithms was 72.9%; both were significantly lower than that of Xpert C. difficile (P < 0.001 and P = 0.03, respectively). The sensitivity of the EIA was significantly lower than that of the Xpert C. difficile assay for detection of ribotypes 002, 027, and 106 (P < 0.0001, P < 0.0001, and P = 0.004, respectively, Fisher's exact test), and the sensitivity of GDH algorithms for ribotypes other than 027 was lower than that for Xpert C. difficile (P < 0.001). The Xpert C. difficile assay is a simple, rapid, and accurate method for detection of toxigenic C. difficile in unformed stool specimens and is minimally affected by strain type compared to EIA and GDH-based methods.

View details for DOI 10.1128/JCM.00427-10

View details for Web of Science ID 000282544700037

View details for PubMedID 20702676
Long-term Shedding of Influenza A Virus in Stool of Immunocompromised Child EMERGING INFECTIOUS DISEASES Pinsky, B. A., Mix, S., Rowe, J., Ikemoto, S., Baron, E. J. 2010; 16 (7): 1165-1167
Abstract

In immunocompromised patients, influenza infection may progress to prolonged viral shedding from the respiratory tract despite antiviral therapy. We describe chronic influenza A virus infection in an immunocompromised child who had prolonged shedding of culturable influenza virus in stool.

View details for DOI 10.3201/eid1607.091248

View details for Web of Science ID 000279522200024

View details for PubMedID 20587197
Clinical Utility of an Automated Instrument for Gram Staining Single Slides JOURNAL OF CLINICAL MICROBIOLOGY Baron, E. J., Mix, S., Moradi, W. 2010; 48 (6): 2014-2015
Abstract

Gram stains of 87 different clinical samples were prepared by the laboratory's conventional methods (automated or manual) and by a new single-slide-type automated staining instrument, GG&B AGS-1000. Gram stains from either heat- or methanol-fixed slides stained with the new instrument were easy to interpret, and results were essentially the same as those from the methanol-fixed slides prepared as a part of the routine workflow. This instrument is well suited to a rapid-response laboratory where Gram stain requests are commonly received on a stat basis.

View details for DOI 10.1128/JCM.02503-09

View details for Web of Science ID 000278118100003

View details for PubMedID 20410348
Mixed infection involving Actinomyces, Aggregatibacter, and Fusobacterium species presenting as perispinal tumor ANAEROBE Ghafghaichi, L., Troy, S., Budvytiene, I., Banaei, N., Baron, E. J. 2010; 16 (2): 174-178
Abstract

A representative case in which a polymicrobial infection involving Fusobacterium nucleatum, Actinomyces israelii and Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans was initially diagnosed as malignancy in an edentulous patient. Additional history obtained after the nature of the syndrome was elucidated revealed that he had had his two remaining teeth extracted four months prior to this episode.

View details for DOI 10.1016/j.anaerobe.2009.07.003

View details for Web of Science ID 000277734600018

View details for PubMedID 19628046
Real-Time PCR Testing for mecA Reduces Vancomycin Usage and Length of Hospitalization for Patients Infected with Methicillin-Sensitive Staphylococci JOURNAL OF CLINICAL MICROBIOLOGY Nguyen, D. T., Yeh, E., Perry, S., Luo, R. F., Pinsky, B. A., Lee, B. P., Sisodiya, D., Baron, E. J., Banaei, N. 2010; 48 (3): 785-790
Abstract

Nucleic acid amplification tests (NAATs) have revolutionized infectious disease diagnosis, allowing for the rapid and sensitive identification of pathogens in clinical specimens. Real-time PCR testing for the mecA gene (mecA PCR), which confers methicillin resistance in staphylococci, has the added potential to reduce antibiotic usage, improve clinical outcomes, lower health care costs, and avoid emergence of drug resistance. A retrospective study was performed to identify patients infected with methicillin-sensitive staphylococcal isolates who were receiving vancomycin treatment when susceptibility results became available. Vancomycin treatment and length of hospitalization were compared in these patients for a 6-month period before and after implementation of mecA PCR. Among 65 and 94 patients identified before and after mecA PCR, respectively, vancomycin usage (measured in days on therapy) declined from a median of 3 days (range, 1 to 44 days) in the pre-PCR period to 1 day (range, 0 to 18 days) in the post-PCR period (P < 0.0001). In total, 38.5% (25/65) of patients were switched to beta-lactam therapy in the pre-PCR period, compared to 61.7% (58/94) in the post-PCR period (P = 0.004). Patient hospitalization days also declined from a median of 8 days (range, 1 to 47 days) in the pre-PCR period to 5 days (range, 0 to 42 days) in the post-PCR period (P = 0.03). Real-time PCR testing for mecA is an effective tool for reducing vancomycin usage and length of stay of hospitalized patients infected with methicillin-sensitive staphylococci. In the face of ever-rising health care expenditures in the United States, these findings have important implications for improving outcomes and decreasing costs.

View details for DOI 10.1128/JCM.02150-09

View details for Web of Science ID 000274996200016

View details for PubMedID 20071556

View details for PubMedCentralID PMC2832423
Preferential Lower Respiratory Tract Infection in Swine-Origin 2009 A(H1N1) Influenza CLINICAL INFECTIOUS DISEASES Yeh, E., Luo, R. F., Dyner, L., Hong, D. K., Banaei, N., Baron, E. J., Pinsky, B. A. 2010; 50 (3): 391-394
Abstract

We report a case of 2009 influenza A(H1N1) virus infection in which virus was detected predominantly in specimens from the lower respiratory tract but was absent or at very low levels in nasopharyngeal swab samples. This presentation suggests that, in certain hosts or for particular variants of 2009 A(H1N1) virus, the lower respiratory tract may be the preferred site of infection.

View details for DOI 10.1086/649875

View details for Web of Science ID 000273500300014

View details for PubMedID 20047483
Diagnosis and Management of Complicated Intra-Abdominal Infection in Adults and Children: Guidelines by the Surgical Infection Society and the Infectious Diseases Society of America SURGICAL INFECTIONS Solomkin, J. S., Mazuski, J. E., Bradley, J. S., Rodvold, K. A., Goldstein, E. J., Baron, E. J., O'Neill, P. J., Chow, A. W., Dellinger, E. P., Eachempati, S. R., Gorbach, S., Hilfiker, M., May, A. K., Nathens, A. B., Sawyer, R. G., Bartlett, J. G. 2010; 11 (1): 79-109
Abstract

Evidence-based guidelines for managing patients with intra-abdominal infection were prepared by an Expert Panel of the Surgical Infection Society and the Infectious Diseases Society of America. These updated guidelines replace those previously published in 2002 and 2003. The guidelines are intended for treating patients who either have these infections or may be at risk for them. New information, based on publications from the period 2003-2008, is incorporated into this guideline document. The panel has also added recommendations for managing intra-abdominal infection in children, particularly where such management differs from that of adults; for appendicitis in patients of all ages; and for necrotizing enterocolitis in neonates.

View details for DOI 10.1089/sur.2009.9930

View details for Web of Science ID 000279013000013

View details for PubMedID 20163262
Diagnosis and Management of Complicated Intra-abdominal Infection in Adults and Children: Guidelines by the Surgical Infection Society and the Infectious Diseases Society of America CLINICAL INFECTIOUS DISEASES Solomkin, J. S., Mazuski, J. E., Bradley, J. S., Rodvold, K. A., Goldstein, E. J., Baron, E. J., O'Neill, P. J., Chow, A. W., Dellinger, E. P., Eachempati, S. R., Gorbach, S., Hilfiker, M., May, A. K., Nathens, A. B., Sawyer, R. G., Bartlett, J. G. 2010; 50 (2): 133-164
Abstract

Evidence-based guidelines for managing patients with intra-abdominal infection were prepared by an Expert Panel of the Surgical Infection Society and the Infectious Diseases Society of America. These updated guidelines replace those previously published in 2002 and 2003. The guidelines are intended for treating patients who either have these infections or may be at risk for them. New information, based on publications from the period 2003-2008, is incorporated into this guideline document. The panel has also added recommendations for managing intra-abdominal infection in children, particularly where such management differs from that of adults; for appendicitis in patients of all ages; and for necrotizing enterocolitis in neonates.

View details for DOI 10.1086/649554

View details for Web of Science ID 000273069100002

View details for PubMedID 20034345
Multiplex Pathogen Identification for Polymicrobial Urinary Tract Infections Using Biosensor Technology: A Prospective Clinical Study JOURNAL OF UROLOGY Mach, K. E., Du, C. B., Phull, H., Haake, D. A., Shih, M., Baron, E. J., Liao, J. C. 2009; 182 (6): 2735-2741
Abstract

Rapid diagnosis of urinary tract infection would have a significant beneficial impact on clinical management, particularly in patients with structural or functional urinary tract abnormalities who are highly susceptible to recurrent polymicrobial infections. We examined the analytical validity of an electrochemical biosensor array for rapid molecular diagnosis of urinary tract infection in a prospective clinical study in patients with neurogenic bladder.The electrochemical biosensor array was functionalized with DNA probes against 16S rRNA of the most common uropathogens. Spinal cord injured patients at a Veterans Affairs hospital were recruited into the study. Urine samples were generally tested on the biosensor within 1 to 2 hours of collection. Biosensor results were compared with those obtained using standard clinical microbiology laboratory methods.We successfully developed a 1-hour biosensor assay for multiplex identification of pathogens. From July 2007 to December 2008 we recruited 116 patients, yielding a total of 109 urine samples suitable for analysis and comparison between biosensor assay and standard urine culture. Of the samples 74% were positive, of which 42% were polymicrobial. We identified 20 organisms, of which Escherichia coli, Pseudomonas aeruginosa and Enterococcus species were the most common. Biosensor assay specificity and positive predictive value were 100%. Pathogen detection sensitivity was 89%, yielding a 76% negative predictive value.To our knowledge we report the first prospective clinical study to successfully identify pathogens within a point of care time frame using an electrochemical biosensor platform. Additional efforts to improve the limit of detection and probe design are needed to further enhance assay sensitivity.

View details for DOI 10.1016/j.juro.2009.08.028

View details for Web of Science ID 000271668600072

View details for PubMedID 19837423
Comparison of Real-Time PCR and Conventional Biochemical Methods for Identification of Staphylococcus lugdunensis JOURNAL OF CLINICAL MICROBIOLOGY Pinsky, B. A., Samson, D., Ghafghaichi, L., Baron, E. J., Banaei, N. 2009; 47 (11): 3472-3477
Abstract

Staphylococcus lugdunensis is an aggressive, virulent member of the coagulase-negative staphylococci (CoNS) that is responsible for severe, rapidly progressive skin and soft tissue infections and native valve endocarditis. To facilitate prompt identification and appropriate therapy, we describe here a rapid and robust multiplex real-time PCR assay that is able to definitively distinguish S. lugdunensis from other staphylococci. Using melting curve analysis, the assay also identifies Staphylococcus aureus and CoNS other than S. lugdunensis and determines MecA-dependent resistance to methicillin (meticillin). When applied to a panel of well-characterized staphylococcal reference strains, as well as 165 clinical isolates previously identified by conventional methods, the assay was both sensitive and specific for S. lugdunensis, correctly identifying the reference strain and all 47 S. lugdunensis isolates without inappropriate amplification of other staphylococci. Furthermore, rapid biochemical identification using the WEE-TAB system to detect ornithine decarboxylase activity was found to be unsuitable as an alternative to PCR identification, displaying just 31% sensitivity and 77% specificity when tested on a subset (90 isolates) of the clinical strains. We therefore propose that this simple, accurate PCR approach will allow for the routine and timely identification of S. lugdunensis in the clinical microbiology laboratory.

View details for DOI 10.1128/JCM.00342-09

View details for Web of Science ID 000271373000013

View details for PubMedID 19741081
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
Growth of Histoplasma capsulatum isolates is better on potato dextrose agar with chloramphenicol than on brain heart infusion agar JOURNAL DE MYCOLOGIE MEDICALE Burtelow, M. A., Merker, J. D., Baron, E. J. 2009; 19 (3): 197-199
View details for DOI 10.1016/j.mycmed.2009.04.002

View details for Web of Science ID 000270282800008
Hair Sheep Blood, Citrated or Defibrinated, Fulfills All Requirements of Blood Agar for Diagnostic Microbiology Laboratory Tests PLOS ONE Yeh, E., Pinsky, B. A., Banaei, N., Baron, E. J. 2009; 4 (7)
Abstract

Blood agar is used for the identification and antibiotic susceptibility testing of many bacterial pathogens. In the developing world, microbiologists use human blood agar because of the high cost and inhospitable conditions for raising wool sheep or horses to supply blood. Many pathogens either fail to grow entirely or exhibit morphologies and hemolytic patterns on human blood agar that confound colony recognition. Furthermore, human blood can be hazardous to handle due to HIV and hepatitis. This study investigated whether blood from hair sheep, a hardy, low-maintenance variety of sheep adapted for hot climates, was suitable for routine clinical microbiology studies.Hair sheep blood obtained by jugular venipuncture was anticoagulated by either manual defibrination or collection in human blood bank bags containing citrate-phosphate-dextrose. Trypticase soy 5% blood agar was made from both forms of hair sheep blood and commercial defibrinated wool sheep blood. Growth characteristics, colony morphologies, and hemolytic patterns of selected human pathogens, including several streptococcal species, were evaluated. Specialized identification tests, including CAMP test, reverse CAMP test, and satellite colony formation with Haemophilus influenzae and Abiotrophia defectiva were also performed. Mueller-Hinton blood agar plates prepared from the three blood types were compared in antibiotic susceptibility tests by disk diffusion and E-test.The results of all studies showed that blood agar prepared from citrated hair sheep blood is suitable for microbiological tests used in routine identification and susceptibility profiling of human pathogens. The validation of citrated hair sheep blood eliminates the labor-intensive and equipment-requiring process of manual defibrination. Use of hair sheep blood, in lieu of human blood currently used by many developing world laboratories and as an alternative to cost-prohibitive commercial sheep blood, offers the opportunity to dramatically improve the safety and accuracy of laboratory diagnosis of pathogenic bacteria in resource-poor countries.

View details for DOI 10.1371/journal.pone.0006141

View details for Web of Science ID 000267806300010

View details for PubMedID 19578541
Pediatric and Neonatal Staphylococcus aureus Bacteremia: Epidemiology, Risk Factors, and Outcome 48th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy/46th Annual Meeting of the Infectious-Diseases-Society-of-America Burke, R. E., Halpern, M. S., Baron, E. J., Gutierrez, K. UNIV CHICAGO PRESS. 2009: 636–44
Abstract

To evaluate the impact of methicillin-resistant Staphylococcus aureus on the prevalence of S. aureus bloodstream infection among children.Retrospective analysis of demographic data, risk factors for infection, and clinical outcomes for children (age, less than 18 years) with S. aureus bacteremia hospitalized at a children's hospital during 2001-2006.We identified 164 episodes of S. aureus bacteremia among 151 children. The prevalence of bacteremia due to methicillin-susceptible S. aureus during 2001-2003 was approximately the same as that during 2004-2006 (29 and 30 cases, respectively, per 10,000 hospitalized children [hereafter, "per 10,000 hospitalizations"]), but the prevalence of bacteremia due to methicillin-resistant S. aureus increased from 4 to 11 cases, respectively, per 10,000 hospitalizations (P=.015). A total of 48% of infections involved children who had S. aureus-positive blood cultures less than 3 days after hospital admission. Seventy-four percent of these children had a preexisting comorbidity. When the prevalence of S. aureus bacteremia was stratified by race, sex, or age, neonates hospitalized at birth and Hispanic children had significantly reduced risks of infection. Children younger than 1 year of age (excluding neonates hospitalized at birth) had an increased prevalence of hospital-onset S. aureus bacteremia. There was a disproportionate increase in the risk of S. aureus bacteremia for each additional week of hospitalization among children with hospital-onset S. aureus bacteremia. Children with methicillin-resistant S. aureus bacteremia had a longer hospital stay, were transferred to another facility at a greater rate than they were discharged home, and had a greater mortality rate, compared with children with methicillin-susceptible S. aureus bacteremia.This study documents the prevalence of S. aureus bacteremia among children with a high risk for acquiring this infection, and it describes populations of children who are at higher risk for bacteremia due to either methicillin-susceptible or methicillin-resistant S. aureus. Methods to improve prevention of S. aureus bacteremia are needed for children with healthcare-associated risk factors for S. aureus bacteremia.

View details for DOI 10.1086/597521

View details for Web of Science ID 000266826600004

View details for PubMedID 19496643
Bartholin's abscess caused by hypermucoviscous Klebsiella pneumoniae JOURNAL OF MEDICAL MICROBIOLOGY Pinsky, B. A., Baron, E. J., Janda, J. M., Banaei, N. 2009; 58 (5): 671-673
Abstract

Klebsiella pneumoniae serogroups displaying the hypermucoviscosity phenotype are associated with a distinct clinical syndrome characterized by liver abscesses, bacteraemia and metastatic lesions. We describe here what we believe to be the first reported case of hypermucoviscous K. pneumoniae causing a superficial Bartholin's abscess in the absence of systemic involvement.

View details for DOI 10.1099/jmm.0.006734-0

View details for Web of Science ID 000266018900019

View details for PubMedID 19369531
Trends in invasive disease due to Candida species following heart and lung transplantation TRANSPLANT INFECTIOUS DISEASE Schaenman, J. M., Rosso, F., Austin, J. M., Baron, E. J., Gamberg, P., Miller, J., Oyer, P. E., Robbins, R. C., Montoya, J. G. 2009; 11 (2): 112-121
Abstract

Although invasive candidiasis (IC) causes significant morbidity and mortality in patients who undergo heart, lung, or heart-lung transplantation, a systematic study in a large cohort of thoracic organ transplant recipients has not been reported to date. Clinical and microbiological data were reviewed for 1305 patients who underwent thoracic organ transplantation at Stanford University Medical Center between 1980 and 2004. We identified and analyzed 76 episodes of IC in 68 patients (overall incidence 5.2% per patient).The incidence of IC was higher in lung (LTx) and heart-lung transplant (HLTx) recipients as compared with heart transplant (HTx) recipients (risk ratio [RR] 1.7, 95% confidence interval [CI] 1.1-2.7).The incidence of IC decreased over time in all thoracic organ transplant recipients, decreasing from 6.1% in the 1980-1986 time period to 2.1% in the 2001-2004 era in the HTx recipients, and from 20% in the 1980-1986 period to 1.8% in the 2001-2004 period in the LTx and HLTx recipients.The most common site of infection differed between the HTx and LTx cohorts, with bloodstream or disseminated disease in the former and tracheobronchitis in the latter. IC in the first year after transplant was significantly associated with death in both HTx (RR 2.9, 95% CI 1.8-4.6, P=0.001) and LTx and HLTx patients (RR 3.0, 95% CI 1.9-4.6, P<0.001). The attributable mortality from IC decreased during the 25-year period of observation, from 36% to 20% in the HTx recipients and from 39% to 15% in the LTx and HLTx recipients. There were a significant number of cases caused by non-albicans Candida species in all patients, with a trend toward higher mortality in the HTx group. In conclusion, the incidence and attributable mortality of IC in thoracic organ transplant recipients has significantly declined over the past 25 years.The use of newer antifungal agents for prophylaxis and treatment, the decrease in the incidence of cytomegalovirus disease, and the use of more selective immunosuppression, among other factors, may have been responsible for this change.

View details for DOI 10.1111/j.1399-3062.2009.00364.x

View details for Web of Science ID 000265015600004

View details for PubMedID 19254327
Challenges and Pitfalls of Morphologic Identification of Fungal Infections in Histologic and Cytologic Specimens A Ten-Year Retrospective Review at a Single Institution AMERICAN JOURNAL OF CLINICAL PATHOLOGY Sangoi, A. R., Rogers, W. M., Longacre, T. A., Montoya, J. G., Baron, E. J., Banaei, N. 2009; 131 (3): 364-375
Abstract

Despite the advantages of providing an early presumptive diagnosis, fungal classification by histopathology can be difficult and may lead to diagnostic error. To assess the accuracy of histologic diagnosis of fungal infections vs culture ("gold standard"), we performed a 10-year retrospective review at our institution. Of the 47 of 338 positive mold and yeast cultures with concurrent surgical pathology evaluation without known history of a fungal infection, 37 (79%) were correctly identified based on morphologic features in histologic and/or cytologic specimens. The 10 discrepant diagnoses (21%) included misidentification of septate and nonseptate hyphal organisms and yeast forms. Errors resulted from morphologic mimics, use of inappropriate terminology, and incomplete knowledge in mycology. The accuracy did not correlate with preceding antifungal therapy (P = .14) or use of special stains (P = .34) and was not operator-dependent. Among 8 discrepancies with clinical follow-up available, 2 potential adverse clinical consequences resulted. While histopathologic identification of fungi in tissue sections and cytologic preparations is prone to error, implementation of a standardized reporting format should improve diagnostic accuracy and prevent adverse outcomes.

View details for DOI 10.1309/AJCP99OOOZSNISCZ

View details for Web of Science ID 000263427400008

View details for PubMedID 19228642
Implementing a real-time PCR assay for rapid surveillance of MRSA. MLO: medical laboratory observer Persing, D., Baron, E. J. 2009; 41 (2): 18-?
View details for PubMedID 19306669
Evaluation of the Biomic V3 microbiology system for identification of selected species on BBL CHROMagar orientation agar and CHROMagar MRSA medium JOURNAL OF CLINICAL MICROBIOLOGY Baron, E. J., D'Souza, H., Wang, A. Q., Gibbs, D. L. 2008; 46 (10): 3488-3490
Abstract

The Biomic V3 microbiology system identifies bacteria by reading the color of colonies selected by the user. For CHROMagar orientation, Biomic results agreed with conventional methods for 94% of the strains assayed. For CHROMagar MRSA, Biomic correctly identified 100% of the strains tested and did not misidentify two methicillin-susceptible Staphylococcus aureus strains growing on the plates.

View details for DOI 10.1128/JCM.02460-07

View details for Web of Science ID 000259758900050

View details for PubMedID 18701661

View details for PubMedCentralID PMC2566125
Effect of building construction on Aspergillus concentrations in a hospital INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY Goebes, M. D., Baron, E. J., Mathews, K. L., Hildemann, L. M. 2008; 29 (5): 462-464
Abstract

Air samples taken in a hospital undergoing construction and analyzed with a quantitative polymerase chain reaction (qPCR) assay for the Aspergillus genus did not show elevated concentrations of Aspergillus or particulate matter with a diameter of 5 microm or less in patient areas. Air samples from the construction zone indicated the containment system, which used polyethylene film barrier and negative pressure, was effective.

View details for DOI 10.1086/587189

View details for Web of Science ID 000254898800016

View details for PubMedID 18419373
Bacterial and fungal infections among diagnostic laboratory workers: evaluating the risks DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE Baron, E. J., Miller, J. M. 2008; 60 (3): 241-246
Abstract

Accidental infections acquired in the laboratory environment are not reportable in a formal forum outside the institution, and therefore, there is little opportunity to evaluate such occurrences and learn from them. We evaluated voluntary responses from 88 facilities, 53 large hospitals (>200 beds) or academic institutions, 32 smaller facilities (<200 beds), and 3 national reference diagnostic laboratories. Thirty-eight of the laboratories (43%), 15 large and 23 small facilities, reported no known exposures during 2002 to 2004. Twenty-one laboratories, 17 large and 4 small institutions, reported at least 1 exposure. Even in this small study, laboratory-acquired infections were reported by 29 laboratories (33%), 24 in large facilities and 5 in small sites. Of the organisms causing laboratory-acquired infections in this survey, Shigella was the most common, followed by Brucella, Salmonella, and Staphylococcus aureus. Although Neisseria meningitidis is perceived to be commonly acquired, only 4 cases were reported by the 88 respondents. Recommendations for reducing exposure risks are provided.

View details for DOI 10.1016/j.diagmicrobio.2007.09.016

View details for Web of Science ID 000253893500001

View details for PubMedID 17997259
Techniques: Collection and Handling of Clinical MIcrobiological Specimens. Encyclopedia of Microbiology, 2nd ed. Ellen Jo Baron, In :Lederberg, J. et al, editors 2008
Differences in clinical and molecular characteristics of skin and soft tissue methicillin-resistant Staphylococcus aureus isolates between two hospitals in northern California JOURNAL OF CLINICAL MICROBIOLOGY Bhattacharya, D., Carleton, H., Tsai, C. J., Baron, E. J., Perdreau-Remington, F. 2007; 45 (6): 1798-1803
Abstract

Community-onset methicillin-resistant Staphylococcus aureus (CO-MRSA) skin and soft tissue infections (SSTI) are associated with SCCmec IV and Panton-Valentine leukocidin (PVL) genes. CO-MRSA epidemiologic studies suggest that genotypic variation exists within one geographic region. We compared MRSA genotypes and demographic and clinical characteristics of patients with CO-MRSA SSTI between two regional medical centers. We also examined factors associated with SCCmec IV and PVL carriage. A total of 279 MRSA SSTI isolates from 2000 to 2002 at San Francisco General Hospital (SFGH) and Stanford University Hospital (SUH) were genotyped by pulsed-field gel electrophoresis and PCR for SCCmec and PVL genes. Medical records were reviewed for clinical characteristics. Ninety-three percent and 69% of MRSA SSTI were caused by CO-MRSA at SFGH and SUH, respectively. Patients with CO-MRSA SSTI at SFGH were more likely to be nonwhite, younger, homeless, and have no previous exposure to health care (P < 0.01). SFGH CO-MRSA strains were more likely to carry SCCmec type IV and PVL genes (90% and 55%, respectively) than SUH strains (29% and 16%, respectively). In multivariate analyses, nonwhite ethnicity was associated with both SCCmec type IV and PVL carriage (odds ratio [OR] of 2.65 and 95% confidence interval [CI] of 1.19 to 5.95 and OR of 1.94 and 95% CI of 1.03 to 3.65, respectively). ST8:USA300:IV became the dominant clone at SFGH, but not at SUH, by 2002. Despite geographic proximity, CO-MRSA SSTI exhibited differing SCCmec types, PVL carriage, and clonal dynamics. CO-MRSA SSTI at SUH were more likely to represent feral isolates of nosocomial origin. Clinicians should assess for nosocomial and community risk factors, realizing that different populations with CO-MRSA SSTI may require separate antimicrobial strategies.

View details for DOI 10.1128/JCM.01747-06

View details for Web of Science ID 000247286500021

View details for PubMedID 17409211

View details for PubMedCentralID PMC1933023
RNA-templated chemistry in cells: Discrimination of Escherichia, Shigella and Salmonella bacterial strains with a new two-color FRET strategy CHEMBIOCHEM Silverman, A. P., Baron, E. J., Kool, E. T. 2006; 7 (12): 1890-1894
View details for DOI 10.1002/cbic.200600278

View details for Web of Science ID 000242981500012

View details for PubMedID 17031884
Implications of new technology for infectious diseases practice CLINICAL INFECTIOUS DISEASES Baron, E. J. 2006; 43 (10): 1318-1323
Abstract

New assays for the diagnosis of infectious diseases--particularly those that use molecular technologies--will revolutionize infectious diseases practices, but the fulfillment of the promise is several years away. Problems with currently available molecular assays include a lack of knowledge about the extent of microbial nucleic acid in "normal" hosts, concentration of agent material in small volume samples, lack of microbiologist expertise, lack of adequate reimbursement, and difficulty with validation based on conventional methods. Clinicians must appreciate the shortcomings of new technology to use it effectively and appropriately. However, we are realizing tangible progress in our ability to detect new etiological agents; the availability of rapid, accurate diagnostic tests for previously difficult infections; and advances into new, human response-based paradigms for diagnostic testing.

View details for Web of Science ID 000241403100016

View details for PubMedID 17051500
Plasma cefazolin levels during cardiovascular surgery: Effects of cardiopulmonary bypass and profound hypothermic circulatory arrest JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Caffarelli, A. D., Holden, J. P., Baron, E. J., Lemmens, H. J., D'Souza, H., Yau, V., Olcott, C., Reitz, B. A., Miller, D. C., van der Starre, P. J. 2006; 131 (6): 1338-1343
Abstract

We sought to assess the effects of cardiopulmonary bypass and profound hypothermic circulatory arrest on plasma cefazolin levels administered for antimicrobial prophylaxis in cardiovascular surgery.Four groups (10 patients per group) were prospectively studied: vascular surgery without cardiopulmonary bypass (group A), cardiac surgery with a cardiopulmonary bypass time of less than 120 minutes (group B), cardiac surgery with a cardiopulmonary bypass time of greater than 120 minutes (group C), and cardiac surgery with cardiopulmonary bypass and profound hypothermic circulatory arrest (group D). Subjects received cefazolin at induction and a second dose before wound closure. Arterial blood samples were obtained preceding cefazolin administration, at skin incision, hourly during the operation, and before redosing. Cefazolin plasma concentrations were determined by using a radial diffusion assay, with Staphylococcus aureus as the indicator microorganism. Cefazolin plasma concentrations were considered noninhibitory at 8 microg/mL or less, intermediate at 16 mug/mL, and inhibitory at 32 microg/mL or greater.In group A cefazolin plasma concentrations remained greater than 16 microg/mL during the complete surgical procedure. In group B cefazolin plasma concentrations diminished to 16 microg/mL or less in 30% of the patients but remained greater than 8 microg/mL. In group C cefazolin plasma concentrations decreased to less than 16 microg/mL in 60% of patients and were less than 8 microg/mL in 50% of patients. In group D cefazolin plasma concentrations reached 16 microg/mL in 66% of the patients but decreased to 8 microg/mL in only 1 patient.For patients undergoing cardiac surgery with a cardiopulmonary bypass time of greater than 120 minutes, a single dose of cefazolin before skin incision with redosing at wound closure does not provide targeted antimicrobial cefazolin plasma levels during the entire surgical procedure. Patients undergoing profound hypothermic circulatory arrest are better protected, but the described protocol of prophylaxis is not optimal.

View details for DOI 10.1016/j.jtcvs.2005.11.047

View details for Web of Science ID 000238023300024

View details for PubMedID 16733167
Rapid diagnosis of tuberculous meningitis: What is the optimal method? INFECTIONS IN MEDICINE Baron, E. J., Carroll, K. C. 2005; 22 (12): 633-637
View details for Web of Science ID 000233864100010
Prolonged incubation and extensive subculturing do not increase recovery of clinically significant microorganisms from standard automated blood cultures CLINICAL INFECTIOUS DISEASES Baron, E. J., Scott, J. D., Tompkins, L. S. 2005; 41 (11): 1677-1680
Abstract

An extensive blood culture protocol, including prolonged incubation of cultures, for 215 patients believed to have had endocarditis yielded only 3 clinically relevant results. Twenty-four Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella (i.e., HACEK) organisms were recovered from standard 5-day blood cultures during the same time period. Specialized methods and not extended incubation times are recommended for recovery of fastidious agents of septicemia.

View details for Web of Science ID 000233018600020

View details for PubMedID 16267743
Comparison of rapid intrapartum screening methods for group B streptococcal vaginal colonization JOURNAL OF MATERNAL-FETAL & NEONATAL MEDICINE Aziz, N., Baron, E. J., D'Souza, H., Nourbakhsh, M., Druzin, M. L., Benitz, W. E. 2005; 18 (4): 225-229
Abstract

To compare optical immunoassay (OIA) and rapid polymerase-chain reaction (PCR) with enrichment broth culture for intrapartum detection of vaginal group B streptococcal (GBS) colonization.Paired vaginal swabs from 315 consecutive term pregnant women at the time of presentation for delivery to a university medical center were tested for GBS by OIA, PCR, and culture. Sensitivity, specificity, and positive and negative predictive values were calculated.Vaginal colonization was identified by culture in 56 subjects (17.8%). The sensitivity of OIA (7.1%, 95% confidence interval 5.1-9.5%) was significantly less than that of unenhanced rapid PCR (62.5%, 95% CI 48.5-74.8%).Neither PCR nor OIA is sufficiently sensitive for intrapartum detection of vaginal GBS colonization. Rapid PCR is more sensitive, but further improvements in technique to increase sensitivity will be necessary if PCR is to have a useful role in the management of women at time of presentation for delivery.

View details for DOI 10.1080/14767050500278048

View details for Web of Science ID 000234009900003

View details for PubMedID 16318971
Laboratory exposures to brucellae and implications for bioterrorism EMERGING INFECTIOUS DISEASES Yagupsky, P., Baron, E. J. 2005; 11 (8): 1180-1185
Abstract

Brucellae are class 3 organisms and potential agents of bioterrorism. Because of effective public health measures, brucellosis has become a rare disease in industrialized countries, and clinical microbiology laboratories are frequently unfamiliar with the genus. A low index of suspicion by physicians or failure to notify the laboratory, equivocal Gram-stain results, misidentification of the organism by commercial systems, unsafe laboratory practices, and laboratory accidents have been responsible for numerous cases of exposure to the organism and laboratory-acquired disease in recent years. Discovery of a laboratory exposure to brucellae should prompt an exhaustive investigation of the event and its circumstances, definition of the population at risk, enforcement of safe laboratory practices, and antimicrobial drug prophylaxis for exposed persons. Inadvertent exposures to brucellae in the clinical laboratory indicate a widespread lack of preparedness to cope with eventual biologic threats involving use of the organism.

View details for Web of Science ID 000230874900003

View details for PubMedID 16102304
BBL CHROMagar Staph aureus is superior to mannitol salt for detection of Staphylococcus aureus in complex mixed infections 43rd Interscience Conference on Antimicrobial Agents and Chemotherapy D'Souza, H. A., Baron, E. J. AMER SOC CLINICAL PATHOLOGY. 2005: 806–8
Abstract

We used 200 sputum specimens from patients with cystic fibrosis to evaluate BBL CHROMagar Staph aureus medium (CSA; BD Diagnostics, Spark, MD). Samples were inoculated to CSA, trypticase soy blood agar (BA), and Mannitol Salt (MS; BD Diagnostics). After 18 hours of incubation, CSA detected 39 (78%) of 50 Staphylococcus aureus (SA) samples; BA detected 30 (60%); and MS detected 29 (58%). Sensitivity after overnight incubation (at least 18 hours) was 82% for CSA, 72% for BA, and 71% for MS. At 2 days, CSA detected 48 (96%) of the SA. There were 2 false-positive results on CSA (99% specificity). There were 4 (8%) minor and no major or very major discrepancies between minimum inhibitory concentration (MIC) results for isolates grown on CSA and those grown on BA. Even at early reading times, CSA was superior to conventional media for detection of SA in these very complex cultures. MICs from all SA samples can be reported 24 hours sooner, and an additional BA subculture is not needed.

View details for DOI 10.1309/FVHR3GRLEQXGBAG

View details for Web of Science ID 000229420000002

View details for PubMedID 15899769
Evaluation of two chromogenic agar media for recovery and identification of Staphylococcus aureus small-colony variants JOURNAL OF CLINICAL MICROBIOLOGY Kipp, F., Kahl, B. C., Becker, K., Baron, E. J., PROCTOR, R. A., Peters, G., Von Eiff, C. 2005; 43 (4): 1956-1959
Abstract

To identify the most rapid and reliable technique for recovery and identification of Staphylococcus aureus small-colony variants (SCVs), the colonial appearance of 106 isolates representing SCVs and the normal phenotype were evaluated on two newly described chromogenic agar media. Although almost all of the SCVs grew on the chromogenic agar media, they did not exhibit a change of color. In comparison with conventional media, S. aureus ID agar (SAID; bioMerieux, La Balme Les Grottes, France) showed the most reliable results, with 49 of 53 SCVs tested growing either as an SCV colony or with a normal phenotype after only 24 h of incubation. Growth of SCVs was often not detected before 72 h of incubation on some of the media tested. In conclusion, the most accurate and rapid method to detect both the species S. aureus and the SCV phenotype is to inoculate specimens onto both Columbia blood agar and SAID.

View details for DOI 10.1128/JCM.43.4.1956-1959.2005

View details for Web of Science ID 000228404100074

View details for PubMedID 15815031
Laboratory-Exposures to Brucellae and Implications for Bioterrorism Emerging Infectious Diseases Yagupsky, P., E.J. Baron 2005; 11 (8)
Evaluation of different culture media for the recovery of Staphylococcus aureus small colony variants (SCVs) Annual Meeting of the DGHM Kipp, F., Kahl, B., Becker, K., Weber, S., Baron, E. J., PROCTOR, R. A., Peters, G., von Eiff, C. ELSEVIER GMBH, URBAN & FISCHER VERLAG. 2004: 141–142
View details for Web of Science ID 000224456000132
Chronic figurate skin lesions - Tinea imbricata CLINICAL INFECTIOUS DISEASES Meites, E., McClenny, N. B., Baron, E. J. 2004; 39 (4): 532-?
View details for Web of Science ID 000223141500016

View details for PubMedID 15362219
Practical bench comparison of BBL CHROMagar Orientation and standard two-plate media for urine cultures JOURNAL OF CLINICAL MICROBIOLOGY D'Souza, H. A., Campbell, M., Baron, E. J. 2004; 42 (1): 60-64
Abstract

A total of 1023 urine samples sent for routine culture were plated onto sheep blood and MacConkey agars and a BBL CHROMagar Orientation (CO; Becton Dickinson, Cockeysville, Md.) plate, and the results were compared. Of these, 250 urine samples (24%) grew >10000 CFU of one or two putative pathogens/ml and 773 showed no growth (NG), mixed growth of <10000 CFU/ml, or three or more strains (mixed). The CO and conventional medium results agreed completely for 595 cultures with NG or <10000 CFU/ml. An additional 178 urine samples yielded clinically insignificant differences. Both medium sets essentially agreed on quantities and identification for 400 single-pathogen cultures and 9 mixed cultures. With the caveat that CO cannot differentiate Klebsiella, Enterobacter, and Serratia spp., enteric pathogens were identified only by morphology and color on CO. Direct visual differentiation of group B streptococci from lactobacilli is not possible, but lactobacillus cells always exhibited easily recognizable morphology on Gram stain. Of 108 paired organism susceptibility results encompassing 2268 drug-pathogen combinations, there were 3% errors and only 1% very major errors. Use of CO allowed a >50% reduction in inoculation time and a >20% reduction in work-up time. For our laboratory, with 50% "no growth" and ca. 25% significant results (50% Escherichia coli), CO allowed time and workup cost savings for a majority of cultures. A cost analysis (time and supplies for our laboratory) showed that if CO is used alone, the break-even level for CO pricing is US dollars 1.78; if CO and blood agar are both used, the break-even pricing for CO is US dollars 1.53.

View details for DOI 10.1128/JCM.42.1.60-64.2004

View details for Web of Science ID 000188121800010

View details for PubMedID 14715732
Comparison of the susceptibilities of Candida spp. to fluconazole and voriconazole in a 4-year global evaluation using disk diffusion JOURNAL OF CLINICAL MICROBIOLOGY Hazen, K. C., Baron, E. J., Colombo, A. L., Girmenia, C., Sanchez-Sousa, A., del Palacio, A., de Bedout, C., Gibbs, D. L. 2003; 41 (12): 5623-5632
Abstract

From June 1997 to December 2001, results of in vitro susceptibility tests of yeast isolates from 35 countries were collected. For 2001 alone, fluconazole results were reported for 22,111 yeast isolates from 77 institutions in 30 countries. Of these isolates, 18,569 were also tested for susceptibility to voriconazole. All study sites tested clinical yeast isolates by recently endorsed NCCLS disk diffusion method M44-P. Disk test plates were automatically read and results were recorded with the BIOMIC Image Analysis System. Species, drug, zone diameter, susceptibility category, MIC, and quality control results were electronically submitted by e-mail quarterly for analysis. Duplicate test results (same patient and same species with same sensitivity-resistance profile and biotype results during any 7-day period) and uncontrolled test results were eliminated from this analysis. The proportion of Candida albicans isolates decreased from 69.7% in 1997 to 1998 to 63.0% in 2001, and this decrease was accompanied by a concomitant increase in C. tropicalis and C. parapsilosis. The susceptibility (susceptible [S]or susceptible-dose dependent [S-DD]) of C. albicans isolates to fluconazole was virtually unchanged, from 99.2% in 1997 to 99% in 2001; the C. glabrata response to fluconazole was unchanged, from 81.5% S or S-DD in 1997 to 81.7% in 2001, although the percentage of resistant isolates from blood and upper respiratory tract samples appeared to increase over the study period; the percentage of S C. parapsilosis isolates decreased slightly, from 98% S or S-DD in 1997 to 96% in 2001; and the percentage of S isolates of C. tropicalis increased slightly, from 95.7% in 1997 to 96.9% in 2001. The highest rate of resistance to fluconazole among C. albicans isolates was noted in Ecuador (7.6%, n = 250). Results from this investigation indicate that the susceptibility of yeast isolates to fluconazole has changed minimally worldwide over the 4.5-year study period and that voriconazole demonstrated 10- to 100-fold greater in vitro activity than fluconazole against most yeast species.

View details for DOI 10.1128/JCM.41.12.5623-5632.2003

View details for Web of Science ID 000187228800042

View details for PubMedID 14662952
Characterization of Salmonella enterica serotype Newport isolated from humans and food animals JOURNAL OF CLINICAL MICROBIOLOGY Zhao, S., Qaiyumi, S., Friedman, S., Singh, R., Foley, S. L., White, D. G., McDermott, P. F., Donkar, T., Bolin, C., Munro, S., Baron, E. J., Walker, R. D. 2003; 41 (12): 5366-5371
Abstract

Salmonella enterica serotype Newport isolates resistant to at least nine antimicrobials (including extended-spectrum cephalosporins), known as serotype Newport MDR-AmpC isolates, have been rapidly emerging as pathogens in both animals and humans throughout the United States. Resistance to extended-spectrum cephalosporins is associated with clinical failures, including death, in patients with systemic infections. In this study, 87 Salmonella serotype Newport strains were characterized by pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing and examined for the presence of class 1 integrons and bla(CMY) genes. Thirty-five PFGE patterns were observed with XbaI, and three of these patterns were indistinguishable among isolates from humans and animals. Fifty-three (60%) Salmonella serotype Newport isolates were identified as serotype Newport MDR-AmpC, including 16 (53%) of 30 human isolates, 27 (93%) of 29 cattle isolates, 7 (70%) of 10 swine isolates, and 3 (30%) of 10 chicken isolates. However, 28 (32%) Salmonella serotype Newport isolates were susceptible to all 16 antimicrobials tested. The bla(CMY) gene was present in all serotype Newport MDR-AmpC isolates. Furthermore, the plasmid-mediated bla(CMY) gene was transferable via conjugation to an Escherichia coli strain. The transconjugant showed the MDR-AmpC resistance profile. Thirty-five (40%) of the isolates possessed class 1 integrons. Sequence analyses of the integrons showed that they contained aadA, which confers resistance to streptomycin, or aadA and dhfr, which confer resistance to trimethoprim-sulfamethoxazole. One integron from a swine isolate contained the sat-1 gene, which encodes resistance to streptothricin, an antimicrobial agent that has never been approved for use in the United States. In conclusion, Salmonella serotype Newport MDR-AmpC was commonly identified among Salmonella serotype Newport isolates recovered from humans and food animals. These findings support the possibility of transmission of this organism to humans through the food chain.

View details for DOI 10.1128/JCM.41.12.5366-5371.2003

View details for Web of Science ID 000187228800002

View details for PubMedID 14662912
Guidelines for the selection of anti-infective agents for complicated intra-abdominal infections CLINICAL INFECTIOUS DISEASES Solomkin, J. S., Mazuski, J. E., Baron, E. J., Sawyer, R. G., Nathens, A. B., Dipiro, J. T., Buchman, T., Dellinger, E. P., Jernigan, J., Gorbach, S., Chow, A. W., Bartlett, J. 2003; 37 (8): 997-1005
View details for Web of Science ID 000185677500001

View details for PubMedID 14523762
Comparison of conventional viral cultures with direct fluorescent antibody stains for diagnosis of community-acquired respiratory virus infections in hospitalized children PEDIATRIC INFECTIOUS DISEASE JOURNAL Shetty, A. K., Treynor, E., Hill, D. W., Gutierrez, K. M., Warford, A., Baron, E. J. 2003; 22 (9): 789-794
Abstract

Because of the widespread availability of rapid viral antigen testing, many institutions never adopted a routine practice of ordering viral cultures to detect community-acquired respiratory viruses (CRVs). The ease of performing complete viral studies in our on site laboratory allowed us to assess the clinical implications of the absence of conventional culture results in previously healthy hospitalized children with CRV infections.From June 1997 through May 2000, the results of direct immunofluorescence assay (DFA) of 1069 nasopharyngeal swab (NP) specimens were compared with simultaneously inoculated conventional tube cell cultures for detection of CRVs. In addition the medical records of 140 previously healthy infants and children hospitalized for management of lower respiratory tract infections caused by culture-proved CRVs were reviewed.Viruses were isolated or detected by DFA or viral culture or both in 468 (30%) of the 1557 NP samples evaluated. The most common CRV isolated was respiratory syncytial virus (49%), followed by parainfluenza viruses (15%), influenza A viruses (14%), rhinoviruses (8%), adenoviruses (4%), enteroviruses (4%) and influenza B viruses (1%). Of the 1069 NP specimens for which both viral culture and rapid antigen testing were performed, 190 specimens were DFA-positive and culture-positive, 7 specimens were DFA-positive and culture-negative, 35 specimens were DFA-negative and culture-positive and 837 specimens were DFA-negative and culture-negative. The overall sensitivity, specificity, positive predictive value and negative predictive value of DFA were 84, 99, 96 and 96%, respectively. Of the 140 hospitalized patients with culture-proved viral cultures (89 respiratory syncytial virus, 22 influenza A, 20 parainfluenza virus and 9 adenovirus), the mean duration of hospital stay was 3.6 days, and the mean time for viral cultures to become positive was 7.7 days (P < 0.001, signed rank test). One hundred twenty (86%) viral cultures did not become positive until after the patient had been discharged from the hospital. In no case was the clinical decision regarding the patient's treatment or discharge from the hospital based on the results of viral culture.We conclude that positive viral cultures have no impact on clinical decision making and management of healthy children during hospitalization for illness attributable to community-acquired respiratory viruses.

View details for Web of Science ID 000185686400008

View details for PubMedID 14506369
Speculations on the microbiology laboratory of the future Anaerobe Odyssey Symposium held in honor of Sydney M Finegolds 80th Birthday Baron, E. J. OXFORD UNIV PRESS INC. 2002: S84–S87
Abstract

Changes in the availability of skilled laboratory personnel, new technologies, and the financial environment will all influence the practice of diagnostic microbiology in the near and more distant future. Because of the special expertise needed for the accurate identification of anaerobic bacteria, the ability to diagnose anaerobic infections may decline as a consequence of these changes. Physicians should anticipate a difficult time in the years between the loss of expertise in traditional methods and development of reliable and accurate molecular assays.

View details for Web of Science ID 000177533400014

View details for PubMedID 12173114
Labor and cost requirements of two commercial assays for qualitative molecular detection of hepatitis C virus JOURNAL OF CLINICAL MICROBIOLOGY Schrijver, I., Baron, E. J. 2002; 40 (9): 3476-3477
Abstract

The Bayer transcription-mediated amplification (TMA) and the Roche PCR Amplicor version 2.0 molecular assays for the qualitative detection of hepatitis C virus were compared for cost, hands-on time, assay duration, and complexity. The TMA assay compares well to PCR and may be especially useful for laboratories with large numbers of test requests.

View details for DOI 10.1128/JCM.40.9.3476-3477.2002

View details for Web of Science ID 000177829900057

View details for PubMedID 12202596
Change in colony morphology of Candida lusitaniae in association with development of amphotericin B resistance ANTIMICROBIAL AGENTS AND CHEMOTHERAPY McClenny, N. B., Fei, H. H., Baron, E. J., Gales, A. C., Houston, A., Hollis, R. J., Pfaller, M. A. 2002; 46 (5): 1325-1328
Abstract

It is not uncommon to see amphotericin B treatment failure in patients with systemic infection caused by Candida lusitaniae. We report a patient with stage IV ovarian carcinoma and C. lusitaniae sepsis whose treatment with amphotericin B failed. The initial blood isolate was susceptible to amphotericin B in vitro; however, the MIC for a blood isolate recovered 7 weeks after treatment began showed a fourfold increase. Direct subculture of two positive blood samples obtained within a week of the patient's death showed the coexistence of two distinct colony color variants on CHROMagar Candida (CAC). One variant was susceptible to amphotericin B, and one was resistant. These results emphasize the importance of repeat amphotericin B susceptibility testing for patients with persistent C. lusitaniae infection. The presence of colony variants on CAC may signal the emergence of amphotericin B resistance in C. lusitaniae and should be investigated.

View details for DOI 10.1128/AAC.46.5.1325-1328.2002

View details for Web of Science ID 000175100800023

View details for PubMedID 11959563
Rapid identification of bacteria and yeast: Summary of a National Committee for Clinical Laboratory Standards proposed guideline CLINICAL INFECTIOUS DISEASES Baron, E. J. 2001; 33 (2): 220-225
Abstract

Using colony morphology on selected agars, Gram-stain morphology, and a number of 1-step biochemical or enzymatic tests, skilled microbiologists can identify the species of the majority of isolates seen routinely in a clinical laboratory. These results are often available more quickly than and are as accurate as those derived from conventional methods. The National Committee for Clinical Laboratory Standards has produced a guideline that describes tests that can be used to identify a number of aerobic gram-negative rods and gram-positive cocci, a number of commonly isolated anaerobes, and 3 species of yeast. An overview of the organisms included in the guideline, the tests that identify them, and the situations in which rapid testing is appropriate is presented here.

View details for Web of Science ID 000169387700012

View details for PubMedID 11418882
Role of clinical microbiology laboratories in the management and control of infectious diseases and the delivery of health care CLINICAL INFECTIOUS DISEASES Peterson, L. R., Hamilton, J. D., Baron, E. J., Tompkins, L. S., MILLER, J. M., WILFERT, C. M., Tenover, F. C., Thomson, R. B. 2001; 32 (4): 605-610
Abstract

Modern medicine has led to dramatic changes in infectious diseases practice. Vaccination and antibiotic therapy have benefited millions of persons. However, constrained resources now threaten our ability to adequately manage threats of infectious diseases by placing clinical microbiology services and expertise distant from the patient and their infectious diseases physician. Continuing in such a direction threatens quality of laboratory results, timeliness of diagnosis, appropriateness of treatment, effective communication, reduction of health care-associated infections, advances in infectious diseases practice, and training of future practitioners. Microbiology laboratories are the first lines of defense for detection of new antibiotic resistance, outbreaks of foodborne infection, and a possible bioterrorism event. Maintaining high-quality clinical microbiology laboratories on the site of the institution that they serve is the current best approach for managing today's problems of emerging infectious diseases and antimicrobial agent resistance by providing good patient care outcomes that actually save money.

View details for Web of Science ID 000166857900014

View details for PubMedID 11181125
Laboratory response to the challenge of today's medical care environment--using the laboratory cost-effectively to enhance patient care. Current clinical topics in infectious diseases Baron, E. J., Peterson, L. W. 2001; 21: 172-189
View details for PubMedID 11572151
Fecal leukocyte stain has diagnostic value for outpatients but not inpatients JOURNAL OF CLINICAL MICROBIOLOGY Savola, K. L., Baron, E. J., Tompkins, L. S., Passaro, D. J. 2001; 39 (1): 266-269
Abstract

The methylene blue stain for fecal leukocytes (FL) is widely used as an adjunct to slower but more accurate tests of diarrheal etiology, such as stool culture (SCx) or toxin assays for Clostridium difficile. Prior studies investigating the utility of FL for predicting SCx and C. difficile toxin assay (CDTA) results did not evaluate the importance of inpatient versus outpatient status. We conducted a study of patients who submitted a stool specimen to the Stanford Hospital Microbiology Laboratory between May 1998 and April 1999. The results for stool specimens that were tested by FL and by a confirmatory test (either SCx or CDTA) were used to determine whether the FL method helped to predict the results of these tests. Of 797 stools that were tested by FL method and at least one confirmatory test, 502 stools were tested by CDTA, and 473 stools were cultured. The FL test was 14% sensitive and 90% specific for C. difficile with a diagnostic threshold of one white blood cell/high-power field (WBC/HPF). The overall likelihood ratio (LR) for a positive CDTA was 1.4 with a 95% confidence interval (CI) of 0. 5 to 3.7 (P = 0.5) and was similar among inpatients and outpatients. In contrast, the presence of >/=1 WBC/HPF was 52% sensitive and 88% specific for the 27 positive SCx results and helped to predict a positive SCx result (LR, 4.2; 95% CI, 2.7 to 6.5; P < 0.001). The sensitivity of >/=1 WBC/HPF was 57%, and its predictive value for SCx was higher among outpatients (outpatient LR, 5.0; 95% CI, 2.9 to 8.6; P < 0.001; inpatient LR, 1.9; 95% CI, 0.3 to 10.8; P = 0.5). Among inpatients, only 4 (1.5%) of the 273 SCx results were positive, and the presence of >/=1 WBC/HPF was insensitive (25%) and did not predict a positive SCx (LR, 1.9; 95% CI, 0.3 to 10.8; P = 0.5). When the data were reanalyzed using a diagnostic threshold of five WBC/HPF for FL, the predictive power of the FL method was similar. Thus, FL was of no value in predicting CDTA positivity, nor was it helpful in predicting SCx results for inpatients. Neither SCx nor the FL method should routinely be performed on samples from inpatients. Among outpatients, presence of FLs should suggest a bacterial diarrhea in clinically compatible cases.

View details for Web of Science ID 000166468900043

View details for PubMedID 11136781

View details for PubMedCentralID PMC87712
Multilaboratory validation of rapid spot tests for identification of Escherichia coli JOURNAL OF CLINICAL MICROBIOLOGY York, M. K., Baron, E. J., Clarridge, J. E., Thomson, R. B., Weinstein, M. P. 2000; 38 (9): 3394-3398
Abstract

To validate the accuracy of rapid tests for identification of Escherichia coli, five laboratories sequentially collected 1,064 fresh, clinically significant strains with core criteria of indole-positive, oxidase-negative, nonspreading organisms on sheep blood agar plates (BAP), having typical gram-negative rod plate morphology, defined as good growth on gram-negative rod-selective media. An algorithm using beta-hemolysis on BAP, lactose reaction on eosin-methylene blue or MacConkey agar, L-pyrrolidonyl-beta-naphthylamide (PYR), and 4-methylumbelliferyl-beta-D-glucuronide (MUG) was evaluated. Identifications using the algorithm were compared to those obtained using commercial kit system identifications. One thousand strains were E. coli and 64 were not E. coli by kit identifications, which were supplemented with conventional biochemical testing of low probability profiles. Of the 1,064 isolates meeting the core criteria, 294 were beta-hemolytic and did not require further testing to be identified as E. coli. None of the 64 non-E. coli strains were hemolytic, although other indole-positive, lactose-negative species were found to be hemolytic when further strains were examined in a follow-up study. Of the remaining strains, 628 were identified as E. coli by a lactose-positive and PYR-negative reaction. For nonhemolytic, lactose-negative E. coli, PYR was not helpful, but a positive MUG reaction identified 65 of 78 isolates as E. coli. The remaining 13 E. coli strains required kit identifications. This scheme for E. coli identification misidentified three non-E. coli strains as E. coli, for an error rate of 0.3%. A total of 13 kit identifications, 657 PYR tests, and 113 MUG tests were needed to identify 1,000 E. coli strains with the algorithm. The use of this rapid system saves laboratory resources, provides timely identifications, and yields rare misidentifications.

View details for Web of Science ID 000089114500043

View details for PubMedID 10970389
United States geographic bacteria susceptibility patterns DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE Munro, S., Baron, E. J., Robinson, A., Walsh, P., Meier, F. A., Hacek, D. M., Peterson, L. R., Reynolds, J. K., Allen, S. D., COCKERILL, F., Pfaller, M. A., Jones, R. N., Gilligan, P. H., Wait, K., Harrell, L. J., Reller, L. B., Hall, G., Mann, L. M., Woods, G. L., Carroll, K. C., REIMER, L. 1999; 35 (2): 143-151
View details for Web of Science ID 000083267300009
From benchtop to desktop: creative forms for organizing and presenting laboratory data. MLO: medical laboratory observer Stanley, L., Baron, E. J. 1999; 31 (9): 42-?
View details for PubMedID 10621383
Methicillin resistant Staphylococcus aureus outbreak: A consensus panel's definition and management guidelines AMERICAN JOURNAL OF INFECTION CONTROL Wenzel, R. P., Reagan, D. R., Bertino, J. S., Baron, E. J., Arias, K. 1998; 26 (2): 102-110
Abstract

To provide medical personnel with a definition of an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) and guidelines for managing potential outbreaks.Eighteen panel members were chosen from different specialties, types of institutions, and geographic regions. Representatives from the American Society of Consultant Pharmacists, the American Society of Health-Systems Pharmacists, the Society for Healthcare Epidemiology of America, and the National Association of Directors of Nursing Administration participated.In preparation for the conference, panel members reviewed the literature and wrote abstracts outlining their personal opinions on the core issues, which were circulated to all participants. During a weekend conference, the panel summarized the reviewed literature, defined an MRSA outbreak, and developed management guidelines.Published literature, clinical experience, and expert opinion concerning the emergence and subsequent management of MRSA cases in health care institutions.An outbreak of MRSA was defined as either an increase in the rate of MRSA cases or a clustering of new cases due to the transmission of a single microbial strain in the health care institution. An increased rate of cases can be defined statistically or experientially and includes both infected and colonized patients. A potential outbreak should trigger stepwise, multidisciplinary actions consisting of basic epidemiologic procedures (phase I) to form an initial epidemiologic hypothesis of an outbreak (phase II) followed by a standard epidemiologic workup (phase III) and microbiologic studies (phase IV) to confirm the hypothesis. Mupirocin calcium treatments should be considered to decolonize health care workers during the fourth phase, even before typing is completed.Until studies can be conducted to delineate the effectiveness of different recommendations, the proposed guidelines may provide a useful starting point that can be adapted to meet an individual institution's specific needs.

View details for Web of Science ID 000073160400003

View details for PubMedID 9584803
Anaerobic identification flowchart using minimal laboratory resources. 2nd Meeting of the Anaerobe-Society-of-the-Americas Baron, E. J., Citron, D. M. UNIV CHICAGO PRESS. 1997: S143–S146
View details for Web of Science ID A1997XX13600020

View details for PubMedID 9310658
Bilophila wadsworthia: a unique gram-negative anaerobic rod International Congress on Anaerobic Bacteria and Anaerobic Infections Baron, E. J. ELSEVIER SCI LTD. 1997: 83–86
Abstract

Although comprising less than 0.01% of the normal human gastrointestinal microbiota, Bilophila wadsworthia is the third most common anaerobe recovered from clinical material obtained from patients with perforated and gangrenous appendicitis. Since its discovery in 1988, B. wadsworthia has been recovered from clinical specimens associated with a variety of infections, including sepsis, liver abscesses, cholecystitis, Fournier's gangrene, soft tissue abscesses, empyema, osteomyelitis, Bartholinitis, and hidradenitis suppurativa. In addition, it has been found in the saliva and vaginal fluids of asymptomatic adults and even in the periodontal pockets of dogs. The organism is a saccharolytic, fastidious, and is easily recognized by its strong catalase reaction with 15% H2O2, production of hydrogen sulfide, and growth stimulation by bile (oxgall) and pyruvate. Approximately 75% of strains are urease positive. When grown on pyruvate-containing media, > 85% of strains demonstrate beta-lactamase production. Ribosomal RNA-based phylogenetic studies show Bilophila to be a homogeneous species, most closely related to Desulfovibrio species. Both adherence to human cells and endotoxin have been observed, and preliminary work suggests that environmental iron has a role in expression of outer membrane proteins. Penicillin-binding proteins appear to mediate the organism's susceptibility to at least some beta-lactam agents, which induce spheroplast formation that results in a haze of growth on agar dilution susceptibility test plates which is difficult to interpret. Bilophilastrains are inhibited in vitro by most antibiotics.

View details for Web of Science ID A1997XW04900004

View details for PubMedID 16887567
Lack of agreement among two commercial enzyme-linked immunosorbent antibody assays and a conventional immunofluorescence-based method for detecting islet cell autoantibodies CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY Baron, E. J., Weber, D. E., Weide, L. G. 1996; 3 (4): 429-431
Abstract

Two commercial enzyme-linked immunosorbent assays (ELISAs) for antibodies associated with development of insulin-dependent (type 1) diabetes mellitus (IDDM) were evaluated in conjunction with a conventional indirect immunofluorescent-antibody-islet cell antibody (ICA) test and a radioimmunoprecipitation method for detection of insulin autoantibodies in sera from a selected group of patients. The anti-ICA ELISA was positive for only 1 to 17 serum samples from newly diagnosed IDDM patients but yielded false-positive results with 2 of 6 serum samples containing non-diabetes-related autoantibodies. Although the anti-glutamic acid decarboxylase ELISA did not show positive results for sera with other autoantibodies, it was positive for only 4 of 29 serum samples from recently diagnosed IDDM patients and for 49% of 37 indirect immunofluorescent-antibody-ICA test-positive sera. Until the antibodies associated with the development of diabetes are better characterized, allowing better standards for comparison, it will be difficult to evaluate commercial assays in this field.

View details for Web of Science ID A1996UV50300012

View details for PubMedID 8807208
Infectious disease physicians rate microbiology services and practices JOURNAL OF CLINICAL MICROBIOLOGY Baron, E. J., Francis, D., Peddecord, K. M. 1996; 34 (3): 496-500
Abstract

Recent years have seen increasing emphasis on cost containment and quality improvement in clinical laboratory activities. Modifying those activities to enhance clinical relevance is one strategy that should be satisfying to both laboratory scientists and administrators. This guest commentary describes one approach to quality improvement--the use of user surveys to identify areas for improvement. As an initial attempt to define such areas in clinical diagnostic microbiology, infectious disease specialists, targeted for their particular interest and expertise in microbiology laboratory results, were polled and their responses were analyzed. Some of these data have been presented previously (E. J. Baron, D. P. Francis, and K. M. Peddecord, abstr. C-170, p. 520, in Abstracts of the 94th General Meeting of the American Society for Microbiology, 1994; K. M. Peddecord, E. J. Baron, D. P. Francis, and A. S. Benenson, abstr. C-172, p. 520, in Abstracts of the 94th General Meeting of the American Society for Microbiology, 1994; K. M. Peddecord, E. J. Baron, D. P. Francis, and J. A. Drew, Am. J. Clin. Pathol. 105:58-64, 1996). The discussion includes our recommendations for the use of these survey responses, and their limitations, as stimuli to initiate reexamination of certain microbiology laboratory practices in the interest of developing more cost-effective and clinically relevant protocols.

View details for Web of Science ID A1996UD13700002

View details for PubMedID 8904401
Quality perceptions of microbiology services - A survey of infectious diseases specialists AMERICAN JOURNAL OF CLINICAL PATHOLOGY Peddecord, K. M., Baron, E. J., Francis, D., Drew, J. A. 1996; 105 (1): 58-64
Abstract

Opinions about the quality of their primary microbiology laboratory were received from more than 500 practicing infectious diseases specialists by a nationally distributed questionnaire. Approximately 92% of the respondents' primary laboratories were hospital-based. These sophisticated users rated the quality of their microbiology laboratories to be generally high, with bacteriology receiving highest scores and parasitology the lowest scores. Fortunately, the serious problems, such as failing to call a critical result and culture mishandled in the laboratory, were experienced rarely. Laboratories directed by pathologists with specialty microbiology training, PHD microbiologists, and infectious diseases specialists were judged to be of highest quality. American Board of Medical Microbiology certification of the laboratory director was related to higher overall quality perceptions. Whereas physician-customer opinions may not directly measure a laboratory's analytic quality, they are an important performance measure on which laboratories can base quality improvement activities in both service and analytical aspects of performance.

View details for Web of Science ID A1996TQ29000011

View details for PubMedID 8561089
Quality management and the clinical microbiology laboratory Symposium on Healthcare Reform in the 1990s and the Clinical Microbiology Laboratory/34th Interscience Conference on Antimicrobial Agents and Chemotherapy Baron, E. J. ELSEVIER SCIENCE INC. 1995: 23–34
Abstract

Quality management in today's health care environment requires a fresh approach. Laboratories that have traditionally directed their efforts toward meeting the needs of physicians must now also satisfy the needs of society, the greater public health, and the agency's administrators. Technical advances must today be considered in the context of patient care cost-effectiveness or final outcomes. Examples of strategies for improving quality in the laboratory, such as seeking input from all individuals involved in interpreting or using laboratory test results, forming multidisciplinary committees for development of critical pathways, issuing surveys for assessing the level of satisfaction of the laboratory's customers, and providing visual feedback of the results of activities, are described.

View details for Web of Science ID A1995TM30500005

View details for PubMedID 8775509
Impact of CLIA 88 on the Clinical Microbiology Laboratory Symposium on Healthcare Reform in the 1990s and the Clinical Microbiology Laboratory/34th Interscience Conference on Antimicrobial Agents and Chemotherapy Chapin, K., Baron, E. J. ELSEVIER SCIENCE INC. 1995: 35–43
Abstract

The Clinical Laboratory Improvement Amendments (CLIA 88) to the Clinical Laboratory Improvement Act of 1967 continues to undergo transformation since its implementation more than 2 years ago. The law and its subsequent regulatory modifications were intended to promote high quality in and accurate results from laboratory testing procedures, regardless of the site at which testing occurred. A number of federal regulatory agencies and committees such as the Healthcare Financing Administration, the Clinical Improved Amendments Committee, and the Commission on Laboratory Accreditation, as well as numerous new or modified regulations and requirements have gained importance since CLIA 88 was enacted. In this discussion, components of CLIA 88 that have the greatest impact on clinical microbiology laboratories are presented. In addition, the potential future significance of CLIA 88 are outlined.

View details for Web of Science ID A1995TM30500006

View details for PubMedID 8775510
GENETIC-ASPECTS OF METHICILLIN RESISTANCE IN STAPHYLOCOCCUS-AUREUS AND METHODS USED FOR ITS DETECTION IN CLINICAL LABORATORIES IN THE UNITED-STATES Advisory Workshop on Staphylococcal Infections Baron, E. J. E I F T SRL. 1995: 87–92
Abstract

The mecA gene in methicillin-resistant Staphylococcus aureus (MRSA) directs production of a novel penicillin-binding protein (PBP 2A), an enzyme active in cell wall synthesis. MecA, alone, however, does not determine the degree of resistance expressed by strains of MRSA. Differential resistance or variations in other genes that participate in cell wall synthesis, such as laboratory mutant fem genes, may account, in part, for the heterogeneity of methicillin resistance expression in MRSA. The exact mechanisms of methicillin resistance expression in clinical isolates remain to be elucidated. Laboratories use selective agars containing oxacillin and turbidity pattern recognition programs in automated instruments to identify MRSA, although not all mecA-containing strains are detected. Until a rapid and inexpensive DNA probe assay is widely available, newer test methods such as the E test (AB Biodisk), oxidation-reduction indicators in MIC trays (Alamar), and the rapid fluorescent BBl. Crystal system seem promising.

View details for Web of Science ID A1995TG38000014

View details for PubMedID 8609543
SURVIVAL OF ANAEROBES IN ORIGINAL SPECIMENS TRANSPORTED BY OVERNIGHT MAIL SERVICES 1994 Meeting of the Anaerobe-Society-of-the-Americas Baron, E. J., Strong, C. A., McTeague, M., Vaisanen, M. L., Finegold, S. M. UNIV CHICAGO PRESS. 1995: S174–S177
Abstract

Overnight mail delivery was evaluated for its effect on the recovery of facultative and anaerobic microbes in cultures of clinical specimens from patients. Ten clinical specimens, which were collected at different geographic locations and during different weather conditions, were cultured at the site and after overnight delivery to a distant laboratory. Forty-five facultative anaerobic isolates and 48 anaerobes were recovered. There was no significant difference in numbers of strains or relative quantities recovered in cultures of transported and nontransported specimens. With proper collection, transport, and inoculation of specimens, overnight delivery did not compromise recovery of clinically relevant microbes.

View details for Web of Science ID A1995RE28700017

View details for PubMedID 7548545
EFFECT OF IRON DEPLETION ON PROTEIN PROFILES OF BILOPHILA-WADSWORTHIA 1994 Meeting of the Anaerobe-Society-of-the-Americas Daniel, C., Baron, E. J., Courcol, R. J. UNIV CHICAGO PRESS. 1995: S158–S159
View details for Web of Science ID A1995RE28700012

View details for PubMedID 7548540
STREPTOCOCCUS-MILLERI STRAINS DISPLAYING A GLIDING TYPE OF MOTILITY INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY Bergman, S., Selig, M., Collins, M. D., FARROW, J. A., Baron, E. J., Dickersin, G. R., Ruoff, K. L. 1995; 45 (2): 235-239
Abstract

Isolates belonging to the "Streptococcus milleri" species group that appear to exhibit a gliding type of motility, which is expressed as spreading growth on certain types of agar media, are described. These strains resembled a biotype of "S. milleri" that is usually isolated from genitourinary sources and is notable for its ability to ferment a wide array of carbohydrates. This biotype, which is currently included in the species Streptococcus anginosus, has been implicated in cases of neonatal infection. The "S. milleri" isolates which we studied lacked any observable organelles of motility and gave negative results when they were tested in conventional motility test medium stab cultures. Colonies growing on certain agar media, however, spread over the surfaces of plates and increased in area with increasing time of incubation. Chocolate agar supported maximum spreading, while this characteristic was barely discernible on blood agar. Electron microscopy studies revealed that there was more production of extracellular glycocalyx by motile strains than by a nonmotile isolate having a similar biotype. The results of an analysis of 16S rRNA gene sequences suggested that the motile strains are closely related to S. anginosus and represent a distinct rRNA population within the "S. milleri" species complex.

View details for Web of Science ID A1995QR83400007

View details for PubMedID 7537057
NATIONAL SURVEY OF THE IN-VITRO SPECTRUM OF PIPERACILLIN-TAZOBACTAM TESTED AGAINST MORE THAN 40,000 AEROBIC CLINICAL ISOLATES FROM 236 MEDICAL-CENTERS DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE Baron, E. J., Jones, R. N. 1995; 21 (3): 141-151
Abstract

Hospital microbiology laboratories from 41 states participated in a bacterial antimicrobial susceptibility study comparing in vitro results generated by the standardized disk diffusion method. Over 41,000 freshly isolated aerobic and facultative strains, representing all specimen types (except stools and urines), were tested for their susceptibility to piperacillin-tazobactam and 21 other antimicrobial agents. Enterococcus spp. was the second or third most common isolate from intraabdominal, gynecologic, and cutaneous infections, confirming its growing importance as a nosocomial pathogen. Escherichia coli was the most frequent isolate overall, despite the exclusion of urinary tract specimens from the study. Pseudomonas aeruginosa was the second most prevalent species, ranking first in frequency of recovery from lower-respiratory-tract specimens. Piperacillin-tazobactam was the most active beta-lactamase inhibitor combination tested against Gram-negative bacteria. Its activity against Gram-positive bacteria and Haemophilus influenzae was similar to that of ampicillin-sulbactam (95-97% susceptible). Imipenem and piperacillin-tazobactam displayed similar spectrums of activity against Gram-positive organisms and Haemophilus influenzae. Against Enterobacteriaceae, piperacillin-tazobactam and ceftazidime exhibited similarly wide spectrums of activity, but with some gaps, particularly among Enterobacter spp. and Citrobacter freundii. In this large-scale in vitro study, piperacillin-tazobactam and imipenem displayed the widest antimicrobial spectrums, inhibiting > 90% of all isolates tested.

View details for Web of Science ID A1995RD46800004

View details for PubMedID 7648835
DEVELOPMENT AND EVALUATION OF A BLOOD-FREE MEDIUM FOR DETERMINING GROWTH-CURVES AND OPTIMIZING GROWTH OF ROCHALIMAEA-HENSELAE JOURNAL OF CLINICAL MICROBIOLOGY SCHWARTZMAN, W. A., NESBIT, C. A., Baron, E. J. 1993; 31 (7): 1882-1885
Abstract

Two strains of Rochalimaea henselae were used to optimize a blood-free growth medium. Seven agar bases, four broths, and combinations of eight supplements were evaluated. Acceptable growth was achieved in media containing Fildes solution and hemin, with the best growth demonstrated in brucella broth or on brucella agar with 6 to 8% Fildes solution and 250 micrograms of hemin per ml. R. henselae utilized hemin in concentrations six times that utilized by Rochalimaea quintana. Erythrocyte membrane was necessary to achieve the full growth-promoting effect of rabbit blood.

View details for Web of Science ID A1993LJ20100038

View details for PubMedID 8349767
SHOULD CLINICAL LABORATORIES ADOPT NEW TAXONOMIC CHANGES - IF SO, WHEN 1ST NORTH AMERICAN CONGRESS ON ANAEROBIC BACTERIA AND ANAEROBIC INFECTIONS Baron, E. J., Allen, S. D. OXFORD UNIV PRESS INC. 1993: S449–S450
View details for Web of Science ID A1993LE91900067

View details for PubMedID 8324167
COMPARISON OF THE ACCU-CULSHURE SYSTEM AND A SWAB PLACED IN A B-D PORT-A-CUL TUBE FOR SPECIMEN COLLECTION AND TRANSPORT 1ST NORTH AMERICAN CONGRESS ON ANAEROBIC BACTERIA AND ANAEROBIC INFECTIONS Baron, E. J., Vaisanen, M. L., McTeague, M., Strong, C. A., Norman, D., Finegold, S. M. OXFORD UNIV PRESS INC. 1993: S325–S327
Abstract

We compared the Accu-CulShure guarded specimen collection device and a swab inserted into a B-D Port-a-Cul transport tube in terms of their efficacy under ideal conditions for recovery of bacteria from 10 decubitus ulcer specimens. Cultures yielded 57 aerobes and 21 anaerobes; 76 isolates were recovered with use of Accu-CulShure, and 72 isolates were recovered with use of Port-a-Cul. Both systems were comparable for recovery of organisms in terms of quantitative and qualitative results.

View details for Web of Science ID A1993LE91900033

View details for PubMedID 8324141
BACTERICIDAL ACTIVITY OF SELECTED ANTIMICROBIAL AGENTS AGAINST BILOPHILA-WADSWORTHIA AND BACTEROIDES-GRACILIS 1ST NORTH AMERICAN CONGRESS ON ANAEROBIC BACTERIA AND ANAEROBIC INFECTIONS Baron, E. J., Ropers, G., Summanen, P., Courcol, R. J. OXFORD UNIV PRESS INC. 1993: S339–S343
Abstract

Bactericidal assays of Bacteroides gracilis (six strains) and Bilophila wadsworthia (12 strains) in brucella broth with appropriate supplements were performed by the time-kill kinetic method. Antimicrobial agents tested were ampicillin/sulbactam (final concentrations, 16/8 micrograms/mL), ticarcillin/clavulanate (128/2 micrograms/mL), imipenem (8 micrograms/mL), cefoxitin (32 micrograms/mL), chloramphenicol (16 micrograms/mL), clindamycin (4 micrograms/mL), and metronidazole (16 micrograms/mL). Although all antimicrobial agents tested inhibited growth of all Bilophila strains during the first 24 hours, bactericidal activity was variable; only metronidazole was uniformly bactericidal. Most strains of Bilophila showed 1-2 log increases in growth at 6 hours with clindamycin and chloramphenicol. With chloramphenicol, some Bilophila strains tested showed regrowth starting at 30 hours. B. gracilis strains were generally more susceptible to all agents tested. Metronidazole, ticarcillin/clavulanate, chloramphenicol, and imipenem were most active. Several strains of B. gracilis were not killed by ampicillin/sulbactam, clindamycin, or cefoxitin. Activity was variable among strains and antimicrobial agents.

View details for Web of Science ID A1993LE91900037

View details for PubMedID 8324144
CELLULAR FATTY-ACIDS IN FUSOBACTERIUM SPECIES AS A TOOL FOR IDENTIFICATION JOURNAL OF CLINICAL MICROBIOLOGY TUNER, K., Baron, E. J., Summanen, P., Finegold, S. M. 1992; 30 (12): 3225-3229
Abstract

Identification of fusobacteria from clinical specimens currently requires analysis of metabolic end products by gas-liquid chromatography in addition to certain biochemical and enzymatic tests because of the relative biochemical inactivity of these bacteria. Even the finding of pointed, thin gram-negative cells on Gram-stained slides can no longer be relied on for identification of Fusobacterium nucleatum, since at least four other species of fusobacteria have been seen to exhibit similar morphology. We examined 46 clinical isolates and six American Type Culture Collection type strains of fusobacteria by conventional methods and by the Microbial ID Systems MIDI software package for analyzing cellular fatty acid patterns measured by capillary column gas-liquid chromatography. Distinctive patterns of major fatty acids could be used to reliably identify most clinical isolates to the species level. The MIDI system identified 89% of the isolates correctly and provides an alternative to conventional methods.

View details for Web of Science ID A1992JZ91100035

View details for PubMedID 1452706
CLINICAL IMPORTANCE OF BILOPHILA-WADSWORTHIA EUROPEAN JOURNAL OF CLINICAL MICROBIOLOGY & INFECTIOUS DISEASES Finegold, S., Summanen, P., Gerardo, S. H., Baron, E. 1992; 11 (11): 1058-1063
Abstract

Bilophila wadsworthia is an anaerobic, gram-negative, asaccharolytic, urease-positive, bile-resistant, catalase-positive bacillus, originally recovered from infections in patients with gangrenous and perforated appendicitis. Additional isolations from clinical specimens, including pleural fluid, joint fluid, blood and pus from a scrotal abscess, mandibular osteomyelitis and axillary hidradenitis suppurativa are described here. Bilophila is found as normal flora in feces and, occasionally, in saliva and in the vagina. Isolates from humans are usually beta-lactamase positive and therefore resistant to certain beta-lactam antibiotics. Two percent of strains are also resistant to clindamycin.

View details for Web of Science ID A1992KG63300015

View details for PubMedID 1295759
BILOPHILA-WADSWORTHIA ISOLATES FROM CLINICAL SPECIMENS JOURNAL OF CLINICAL MICROBIOLOGY Baron, E. J., Curren, M., Henderson, G., JOUSIMIESSOMER, H., Lee, K., LECHOWITZ, K., Strong, C. A., Summanen, P., TUNER, K., Finegold, S. M. 1992; 30 (7): 1882-1884
Abstract

Bilophila wadsworthia is an anaerobic, gram-negative, asaccharolytic, bile-resistant, catalase-positive bacillus that is usually urease positive and was originally recognized in specimens of peritoneal fluid and tissue from patients with appendicitis. Additional isolations from clinical specimens, including a scrotal abscess, mandibular osteomyelitis, axillary hidradenitis suppurativa, pleural fluid, joint fluid, and blood, are described here.

View details for Web of Science ID A1992HZ75900048

View details for PubMedID 1629348
A MICROBIOLOGICAL COMPARISON BETWEEN ACUTE AND COMPLICATED APPENDICITIS CLINICAL INFECTIOUS DISEASES Baron, E. J., Bennion, R., Thompson, J., Strong, C., Summanen, P., McTeague, M., Finegold, S. M. 1992; 14 (1): 227-231
Abstract

Bacteria recovered from appendiceal specimens from 20 patients with acute appendicitis were compared with those recovered from 19 patients with complicated (gangrenous or perforative) appendicitis. Specimens of both peritoneal fluid and appendiceal tissue from patients with acute appendicitis yielded smaller numbers and fewer species of bacteria in culture than did specimens from patients with more complicated disease (2.3 strains per specimen for the former; 9.9 strains per specimen for the latter). Bacteria were recovered from all 13 cultures of specimens of appendiceal tissue and from 13 of 18 cultures of specimens of peritoneal fluid obtained from patients with gangrenous and perforative appendicitis; however, only eight of 17 cultures of appendiceal specimens and seven of 18 cultures of peritoneal fluid specimens from patients with acute appendicitis yielded bacteria. These findings suggest that some bacteria traverse the intact appendiceal wall prior to perforation and that progressive infection and subsequent tissue damage and necrosis allow larger numbers and varieties of bacteria to move through appendiceal wall tissue and into the peritoneal cavity.

View details for Web of Science ID A1992HD51700037

View details for PubMedID 1571435
GANGRENOUS AND OR PERFORATED APPENDIX - CLINICAL OUTCOME AND INVITRO SUSCEPTIBILITY TESTING SYMP ON THE USE OF CEFOXITIN IN ANAEROBIC AND AEROBIC INFECTIONS Finegold, S. M., Bennion, R. S., Thompson, J. E., Wexler, H. M., Baron, E. J. MCGRAW HILL HEALTHCARE PUBLICATIONS. 1990: 3–12
Abstract

The data from this study indicate that cefoxitin was effective and generally well tolerated in the management of gangrenous and/or perforated appendicitis. No strong correlation was identified between in vitro susceptibility testing results and clinical outcome.

View details for Web of Science ID A1990EC33200001

View details for PubMedID 2120270
SHORT PREREDUCED ANAEROBICALLY STERILIZED (PRAS) BIOCHEMICAL SCHEME FOR IDENTIFICATION OF CLINICAL ISOLATES OF BILE-RESISTANT BACTEROIDES SPECIES JOURNAL OF CLINICAL MICROBIOLOGY Citron, D. M., Baron, E. J., Finegold, S. M., Goldstein, E. J. 1990; 28 (10): 2220-2223
Abstract

The rapid identification of isolates of bile-resistant Bacteroides species has clinical and therapeutic relevance because of differences in their patterns of susceptibility and virulence. Five hundred twenty-one strains of bile-resistant Bacteroides species that were previously identified by conventional biochemical methods were reexamined to determine the minimum essential parameters necessary for correct identification. Rapid tests for bile resistance, indole production, and catalase were combined with a novel scheme for biochemical determination of saccharolytic activity on arabinose, trehalose, rhamnose, and/or xylan that included the postincubation addition of bromthymol blue for visual pH determination. Organisms were inoculated into prereduced anaerobically sterilized (PRAS) carbohydrates directly from plates, and identification was complete within 24 h of obtaining a pure culture. Ninety-three percent of bile-resistant Bacteroides species from routine clinical specimens were identified correctly by this scheme; a small number of other indole-positive strains, B. splanchnicus, B. eggerthii, and B. stercoris, were misidentified as B. uniformis.

View details for Web of Science ID A1990DZ42500014

View details for PubMedID 2229345
SELECTIVE MEDIUM FOR ISOLATION OF BACTEROIDES-GRACILIS JOURNAL OF CLINICAL MICROBIOLOGY Lee, K. W., Baron, E. J., Summanen, P., Finegold, S. M. 1990; 28 (8): 1747-1750
Abstract

A new medium selective for Bacteroides gracilis was developed. The medium is tryptic soy agar (Difco Laboratories, Detroit, Mich.) containing nalidixic acid, teicoplanin, sodium formate, sodium fumarate, and potassium nitrate. All 18 strains of B. gracilis tested grew with only minimal inhibition. Most of the other 214 organisms tested, including most Bacteroides species, other anaerobes, and a substantial number of facultative anaerobes, were significantly inhibited by the medium. In a diagnostic study of 49 clinical specimens (28 patients with intra-abdominal infection, mostly gangrenous or perforated appendicitis), four strains of B. gracilis were isolated (from 4 different patients) on B. gracilis selective agar but were not detected on standard media.

View details for Web of Science ID A1990DP47900015

View details for PubMedID 2144297
INVITRO SUSCEPTIBILITIES OF BACTEROIDES-GRACILIS, FUSOBACTERIUM-MORTIFERUM AND FUSOBACTERIUM-VARIUM TO 17 ANTIMICROBIAL AGENTS JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY Courcol, R. J., Lee, K. W., Downes, J., Wexler, H. M., Baron, E. J., Finegold, S. M. 1990; 26 (1): 157-158
View details for Web of Science ID A1990DT17800026

View details for PubMedID 2211439
THE MICROBIOLOGY OF CHRONIC SINUS DISEASE IN CHILDREN WITH RESPIRATORY ALLERGY JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY Goldenhersh, M. J., Rachelefsky, G. S., Dudley, J., Brill, J., Katz, R. M., ROHR, A. S., SPECTOR, S. L., Siegel, S. C., Summanen, P., Baron, E. J., Finegold, S. 1990; 85 (6): 1030-1039
Abstract

Chronic maxillary sinusitis is common in children with respiratory allergy and is associated with increased morbidity. The bacteriology of chronic sinus disease in these children has not been adequately evaluated. Between May 1987 and January 1988, 12 children (aged 3 to 9 years), all with documented respiratory allergy and chronic respiratory symptoms consistent with chronic sinusitis (greater than 30 days), were fully evaluated. History, physical examination, complete blood count, nasal smear, and Waters x-ray were done. All patients had opacification of one or both maxillary sinuses, failed to respond to multiple courses of antibiotics, and subsequently underwent maxillary sinus aspiration and irrigation. Specimens were cultured for aerobic and anaerobic organisms with standard technique, and sensitivities were obtained. Culture results revealed a single organism (Moraxella [Branhamella] catarrhalis) in five patients, one patient yielded M. catarrhalis plus Streptococcus species, three were negative, and three patients grew multiple organisms (two with multiple aerobic streptococcal species and one patient with aerobic streptococci and Peptostreptococcus). All children received appropriate culture-directed antimicrobial therapy. Sequential biweekly follow-up revealed progressive radiographic clearing and significant symptomatic improvement. M. catarrhalis is a common pathogen, whereas anaerobic organisms are unusual as a cause of chronic maxillary sinusitis in allergic children. Some children, despite negative cultures, may benefit from maxillary sinus irrigation.

View details for Web of Science ID A1990DK50900008

View details for PubMedID 2355153
EVALUATION OF 2 SINGLE-PLATE INCUBATION SYSTEMS AND THE ANAEROBIC CHAMBER FOR THE CULTIVATION OF ANAEROBIC-BACTERIA JOURNAL OF CLINICAL MICROBIOLOGY Downes, J., MANGELS, J. I., Holden, J., Ferraro, M. J., Baron, E. J. 1990; 28 (2): 246-248
Abstract

Three systems that are available for the incubation of anaerobic organisms were evaluated to assess their ability to support the growth of 25 anaerobic stock strains and to successfully recover anaerobic bacteria from clinical specimens. These were the anaerobic chamber, the Anaerobic Pouch System Catalyst-Free (Difco Laboratories, Detroit, Mich.), and the Bio-Bag Environmental Chamber Type A (Marion Scientific, Div. Marion Laboratories, Inc., Kansas City, Mo.). Three study centers were involved, the Wadsworth Anaerobe Laboratory (Los Angeles, Calif.), the Good Samaritan Hospital (San Jose, Calif.), and the Massachusetts General Hospital (Boston). A total of 171 anaerobic organisms were isolated from 49 clinical specimens that were cultured at the three test centers. Of these, 169 (99%) were recovered from media that were incubated in the anaerobic chamber, 163 (95%) were recovered from the Anaerobic Pouch, and 147 (86%) were recovered from the Bio-Bag. A similar trend was seen with the stock strains, in which the anaerobic chamber often supported better growth of the organisms than did either of the bag systems.

View details for Web of Science ID A1990CJ76200016

View details for PubMedID 2179257
THE BACTERIOLOGY OF GANGRENOUS AND PERFORATED APPENDICITIS - REVISITED ANNALS OF SURGERY Bennion, R. S., Baron, E. J., Thompson, J. E., Downes, J., Summanen, P., Talan, D. A., Finegold, S. M. 1990; 211 (2): 165-171
Abstract

By using optimum sampling, transport, and culture techniques in patients with gangrenous or perforated appendicitis, we recovered than has previously been reported. Thirty patients older than 12 years with histologically documented gangrenous or perforated appendicitis had peritoneal fluid, appendiceal tissue, and abscess contents (if present) cultured. Appendiceal tissue was obtained so as to exclude the lumen. A total of 223 anaerobes and 82 aerobic or faculatative bacteria were recovered, an average of 10.2 different organisms per specimen. Twenty-one different genera and more than 40 species were encountered. Bacteroides fragilis group and Escherichia coli were isolated from almost all specimens. Within the B. fragilis group, eight species were represented. Other frequent isolates included Peptostreptococcus (80%), Pseudomonas (40% [P. aeruginosa, 23.3%, other Pseudomonas spp., 16.7%]), B. splanchnicus (40%), B. intermedius (36.7%), and Lactobacillus (36.7%). Interestingly a previously undescribed fastidious gram-negative anaerobic bacillus was isolated from nearly one half of all patients. This organism was found to have low DNA homology (by dot blot) with the known organisms most closely resembling it.

View details for Web of Science ID A1990CL59100008

View details for PubMedID 2405791
Gangrenous and perforated appendicitis with peritonitis: treatment and bacteriology. Clinical therapeutics Bennion, R. S., Thompson, J. E., Baron, E. J., Finegold, S. M. 1990; 12: 31-44
Abstract

A comparison of single-agent antimicrobial therapy in the treatment of patients with perforated or gangrenous appendicitis and peritonitis was performed in a double-blind, randomized, prospective trial. Pathologic documentation of advanced appendicitis and positive intraoperative specimen cultures were required for inclusion in the study. Ceftizoxime (2 gm every 12 hours) and cefoxitin (2 gm every six hours) were compared. There were no significant differences between the treatment groups. Ninety-seven percent of patients treated with ceftizoxime and 89% of those treated with cefoxitin were cured or improved; there was no mortality in either group. By the use of optimal sampling, transport, and culture techniques, the number and diversity of bacteria recovered from these patients with advanced appendicitis were found to be much larger than previously suspected. Peritoneal fluid, abscess contents (if present), and appendiceal tissue (obtained so as to exclude the lumen) were cultured from all patients. An average number of 3.1 aerobic or facultative bacteria species and 8.5 anaerobic species were isolated from each specimen. Twenty-eight different genera and more than 55 species were encountered, including a previously undescribed fastidious gram-negative anaerobic bacillus. Bacteroides fragilis group and Escherichia coli were isolated from almost all specimens, and within the B fragilis group, eight species were represented. The recovery of such an unexpectedly large and diverse flora may be the reason for the therapeutic failures in these patients. We conclude that single-agent antimicrobial therapy in patients with advanced appendicitis and peritonitis is both safe and effective, and, with ceftizoxime, can be accomplished by a twice-daily dosing regimen.

View details for PubMedID 2202510
BILOPHILA-WADSWORTHIA, GEN-NOV AND SP-NOV, A UNIQUE GRAM-NEGATIVE ANAEROBIC ROD RECOVERED FROM APPENDICITIS SPECIMENS AND HUMAN FECES JOURNAL OF GENERAL MICROBIOLOGY Baron, E. J., Summanen, P., Downes, J., Roberts, M. C., Wexler, H., Finegold, S. M. 1989; 135: 3405-3411
Abstract

Strongly catalase-positive Gram-negative anaerobic rods were isolated from approximately half of all intra-abdominal specimens received from patients with gangrenous and perforated appendicitis, and subsequently also from normal faecal specimens. The organism was originally detected on Bacteroides-bile-aesculin (BBE) agar, and grew slowly on non-selective anaerobic media containing blood. It was stimulated by bile and differed from other known genera by being urease- and catalase-positive, and by reducing nitrate. It did not reduce sulphate. Other anaerobic Gram-negative rods showed no homology by DNA dot-blot hybridization. The thermal melting profile of chromosomal DNA showed 39-40 mol% G + C. The whole-cell fatty acid methyl ester profile included cyclic and branched long-chain acids, and differed from those of all other anaerobes that have been tested. beta-Lactamase was not detected. The name Bilophila wadsworthia gen. nov., sp. nov. is proposed for this organism.

View details for Web of Science ID A1989CJ11100024

View details for PubMedID 2636263
COMPARISON OF 3 METHODS FOR DETECTION OF CRYPTOSPORIDIUM OOCYSTS IN A LOW-PREVALENCE POPULATION JOURNAL OF CLINICAL MICROBIOLOGY Baron, E. J., Schenone, C., Tanenbaum, B. 1989; 27 (1): 223-224
Abstract

Four hundred fecal specimens which had been received for routine ova and parasite examination were concentrated by Formalin-ether sedimentation. Sediments were examined as saline and iodine-stained wet preparations and were stained with rhodamine-auramine O and a commercially available monoclonal fluorescent-antibody stain for oocysts of Cryptosporidium species. Examination with the fluorescent stains detected cryptosporidia in both positive specimens (0.5% prevalence), and routine direct wet-preparation examination detected cryptosporidia in one of them. Detection of only low numbers of positive specimens in our nonrisk population argues against routine use of specific and expensive stain reagents.

View details for Web of Science ID A1989R654900052

View details for PubMedID 2643623
VISUAL AND CLINICAL ANALYSIS OF BAC-T-SCREEN URINE SCREEN RESULTS JOURNAL OF CLINICAL MICROBIOLOGY Baron, E. J., TYBURSKI, M. B., ALMON, R., Berman, M. 1988; 26 (11): 2382-2386
Abstract

Of 337 urine specimens evaluated, 75 of the 113 that showed positive readings on the Bac-T-Screen urine-screening instrument were found by subsequent semiquantitative culture to yield either less than 10,000 CFU of mixed bacteria per ml or no growth (less than 100 CFU/ml by our criteria). We tried to determine what factors contributed to the positive Bac-T-Screen results by examining the 75 Bac-T-Screen-positive urine specimens with three visual methods: Gram staining, hemacytometer chamber counting, and filtering through a 5.0-microns-pore-size nitrocellulose filter with subsequent microscopic examination of the stained filter. Somatic cells and other particles present in those urine specimens that yielded positive readings by the Bac-T-Screen included epithelial cells in 43%, crystals and amorphous material in 33%, and leukocytes in 17% of the specimens. There was no relationship between the numbers of particles seen in urine and the magnitude of the relative absorbance reading obtained with the Bac-T-Screen. A retrospective chart review was conducted for patients with positive Bac-T-Screen results and negative cultures. Of the 75 patients, 6 were thought to have urinary tract infections on the basis of clinical criteria; the majority of the remaining 69 patients had clinical histories revealing systemic or urogenital conditions consistent with shedding of particles in the urine. A positive reading by the Bac-T-Screen system seemed to be related to the presence of somatic cells and other particles in urine; bacteriuria was not always detectable in these cases.

View details for Web of Science ID A1988Q532900032

View details for PubMedID 3235667
NOVEL APPLICATION OF VIDEO IMAGE-PROCESSING TO BIOCHEMICAL AND ANTIMICROBIAL SUSCEPTIBILITY TESTING JOURNAL OF CLINICAL MICROBIOLOGY DAMATO, R. F., Isenberg, H. D., McKinley, G. A., Baron, E. J., Tepper, R., Shulman, M. 1988; 26 (8): 1492-1495
Abstract

ALADIN (Analytab Products, Plainview, N.Y.) is an automated instrument that uses video imaging (computer-assisted guided video camera) for the determination of biochemical and antimicrobial susceptibility test reactions. This collaborative investigation compared video-generated results obtained with ALADIN with visually determined findings. Both approaches were used to view identical reactions. Overall agreement for biochemical and antimicrobial susceptibility tests was greater than 95%. This study demonstrates that video imaging is an acceptable approach for determining microbial responses to biochemical and antimicrobial agents and may provide, with appropriate computer modifications, more accurate and reproducible results than are possible by visual scrutiny.

View details for Web of Science ID A1988P340100011

View details for PubMedID 3049657
ERYTHROMYCIN BIOACTIVITY IS STABLE IN OPHTHALMIC OINTMENT USED FOR PROPHYLAXIS OF NEONATAL GONOCOCCAL CONJUNCTIVITIS ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Bialer, M. G., Baron, E. J., Harper, R. G. 1987; 31 (6): 954-955
Abstract

Erythromycin ophthalmic ointment (E. Fougera & Co., Melville, N.Y.) and erythromycin gluceptate standards prepared in ointment base were stored at room temperature and heated at temperatures up to 45 degrees C for as long as 6 h before being assayed for bioactivity. We were unable to detect any significant loss of antibiotic bioactivity.

View details for Web of Science ID A1987H576700026

View details for PubMedID 3619431
VIRIDANS STREPTOCOCCAL ENDOCARDITIS - CLINICAL, MICROBIOLOGICAL, AND ECHOCARDIOGRAPHIC CORRELATIONS JOURNAL OF INFECTIOUS DISEASES SUSSMAN, J. I., Baron, E. J., Tenenbaum, M. J., Kaplan, M. H., GREENSPAN, J., Facklam, R. R., TYBURSKI, M. B., Goldman, M. A., KANZER, B. F., PIZZARELLO, R. A. 1986; 154 (4): 597-603
Abstract

Infections caused by species within the viridans streptococci have been associated with different clinical characteristics. We studied 36 patients with viridans streptococcal endocarditis. Complications were seen in 10 (32%) of 31 patients with native valve endocarditis and four (80%) of five with prosthetic valve endocarditis and included death in two, valve replacement in six, persistent infection in three, emboli in two, and congestive heart failure in nine. Two-dimensional echocardiograms demonstrated vegetations in 26 (72%) of 36, flail mitral valves in seven, disruption of aortic valve prosthesis in one, and perivalvular abscesses in three (two Streptococcus sanguis I and one Streptococcus intermedius I). All twelve patients with native valve endocarditis who suffered complications had vegetations detected by two-dimensional echocardiography, whereas seven patients with native valve endocarditis without vegetations, as detected by two-dimensional echocardiography, had no complications (P = .03). We found no significant correlation between streptococcal species and clinical outcome. To confirm our identifications, we sent 16 identical viridans streptococcal endocarditis isolates to five institutions; only three of 16 were identified as the same species by all five institutions. We conclude that viridans streptococcal endocarditis can be associated with a virulent clinical course and that there is marked variability in species designations of individual strains by different laboratories.

View details for Web of Science ID A1986E113400007

View details for PubMedID 3745973
AMIKACIN, ETHAMBUTOL, AND RIFAMPIN FOR TREATMENT OF DISSEMINATED MYCOBACTERIUM-AVIUM-INTRACELLULARE INFECTIONS IN PATIENTS WITH ACQUIRED-IMMUNE-DEFICIENCY-SYNDROME DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE Baron, E. J., Young, L. S. 1986; 5 (3): 215-220
Abstract

Synergistic combinations of achievable serum levels of amikacin, rifampin, and ethambutol were tested for their ability to inhibit growth of Mycobacterium avium-intracellulare strains isolated from seven patients with acquired immune deficiency syndrome. Even when the isolates were very resistant to the individual antimicrobial agents in vitro, growth was completely inhibited by all combinations of the three agents tested. Four of the patients treated with a combined regimen of amikacin, rifampin, and ethambutol showed clinical improvement. Synergistic antimicrobial susceptibility tests seem to more accurately represent the efficacy of combined regimens used to treat these extremely resistant mycobacteria than do conventional susceptibility determinations with individual antimicrobial agents.

View details for Web of Science ID A1986D775200004

View details for PubMedID 3757474
CLINICAL MANIFESTATIONS AND THERAPY OF LACTOBACILLUS ENDOCARDITIS - REPORT OF A CASE AND REVIEW OF THE LITERATURE REVIEWS OF INFECTIOUS DISEASES SUSSMAN, J. I., Baron, E. J., Goldberg, S. M., Kaplan, M. H., PIZZARELLO, R. A. 1986; 8 (5): 771-776
Abstract

A case of Lactobacillus casei endocarditis that occurred on a Carpentier-Edwards porcine valve is reported. A review of the literature, which yielded 23 other reports of endocarditis due to this organism, suggests that Lactobacillus is a rare cause of endocarditis. Typically, it occurs in a patient with preexisting structural heart disease (20 of 24 [83%]) and often with some form of recent dental infection or manipulation (18 of 24 [75%]). Six (25%) of 24 patients died of this infection; however, only one (5%) of 19 who were treated with adequate antimicrobial therapy died. The response to antimicrobial therapy was better in the more recent cases. Of those 18 patients who completed a full course of therapy, seven (39%) experienced a relapse; five of these were cured of their infection with a second course of antimicrobial therapy, which usually included higher doses of intravenous penicillin. Our case represents the second reported case that required surgical intervention for cure. Embolic phenomena occurred in 10 (42%) of 24 cases. Various combinations of antibiotics have been successful in achieving cure; however, at present, high-dose penicillin (greater than 25 million units/day) in combination with an aminoglycoside for a period of six weeks appears to be the optimum therapy.

View details for Web of Science ID A1986E295800011

View details for PubMedID 3097786
ANTIGENIC DISTINCTIVENESS OF MOBILUNCUS-CURTISII AND MOBILUNCUS-MULIERIS JOURNAL OF CLINICAL MICROBIOLOGY Roberts, M. C., Baron, E. J., Finegold, S. M., Kenny, G. E. 1985; 21 (6): 891-893
Abstract

A total of 26 Mobiluncus strains (17 M. curtisii and 9 M. mulieris strains) were compared serologically by double immunodiffusion and immunoblotting against antisera prepared against representative isolates of each species. All strains from the same species were strongly reactive with homologous antisera but generally weakly reactive with antisera to the heterologous Mobiluncus spp. The antisera did not react with strains of the unrelated genera Campylobacter, Succinivibrio, Wolinella, Actinomyces, Anaerobiospirillum, and Anaerovibrio.

View details for Web of Science ID A1985AHW2900006

View details for PubMedID 3924951
BIOCHEMICAL AND POLYACRYLAMIDE-GEL ELECTROPHORETIC ANALYSES OF VAGINOSIS-ASSOCIATED ANAEROBIC CURVED RODS SCANDINAVIAN JOURNAL OF UROLOGY AND NEPHROLOGY Baron, E. J., Wexler, H. M., Finegold, S. M. 1985: 65-69
View details for Web of Science ID A1985AJE1000006
BIOACTIVITY OF IMIPENEM AS A FUNCTION OF MEDIUM, TIME, AND TEMPERATURE ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Baron, E. J., Hindler, J. A. 1984; 25 (6): 781-782
Abstract

The bioactivity of imipenem at 20 micrograms/ml in various agar and broth media which are commonly used in susceptibility test assays was measured at different storage temperatures over time. Imipenem was found to be more stable at 4 degrees C than at -20 degrees C and least stable in all media at 35 degrees C.

View details for Web of Science ID A1984SU67100024

View details for PubMedID 6588920
COMPARISON OF SUSCEPTIBILITIES OF ANAEROBIC-BACTERIA DETERMINED BY AGAR DILUTION AND BY A MICROBROTH METHOD REVIEWS OF INFECTIOUS DISEASES Baron, E. J., Bruckner, D. A. 1984; 6: S249-S253
Abstract

The minimal inhibitory concentrations (MICs) of 110 anaerobic bacteria (84% fresh clinical isolates) to nine antimicrobial agents were determined simultaneously by the tentative reference agar-dilution method of the National Committee for Clinical Laboratory Standards and a prototype commercial microbroth panel (Microscan). MICs (determined visually for either system) differed by greater than 1 log2 dilution in 17% of all tests. With the exceptions of the MICs of tetracycline and moxalactam, however, all compared antimicrobial MICs were within 1 log2 dilution for at least 82% of all tests. Twenty-three anaerobic bacterial strains (21%) failed to grow in the microdilution panel (Wilkins-Chalgren broth), and seven strains (6%) failed to grow on the reference Wilkins-Chalgren agar. However, for those bacterial strains that could be tested, the microbroth panel appeared to be less cumbersome than the agar-dilution procedure for susceptibility testing of anaerobic microorganisms.

View details for Web of Science ID A1984SV22200042

View details for PubMedID 6718938
INEFFICIENT INVITRO KILLING OF VIRULENT OR NONVIRULENT SALMONELLA-TYPHIMURIUM BY MURINE POLYMORPHONUCLEAR NEUTROPHILS CANADIAN JOURNAL OF MICROBIOLOGY Baron, E. J., PROCTOR, R. A. 1984; 30 (10): 1264-1270
Abstract

The bactericidal capability of murine peritoneal polymorphonuclear neutrophils against virulent and nonvirulent Salmonella typhimurium was examined in an in vitro system. Although preincubation of the bacteria in specific murine antiserum elicited greater chemiluminescence from phagocytizing neutrophils than did incubation in normal murine serum, antiserum did not enhance ingestion, as less than 5% of the challenge was taken up by neutrophils under any of the conditions studied. Nonvirulent salmonellae showed a transient decrease in viable numbers early during in vitro incubation with or without intact neutrophils. Virulent salmonellae, however, were able to multiply without a lag period except when these bacteria were pretreated with antiserum and incubated in association with intact murine neutrophils. Results of these in vitro studies suggest that the murine polymorphonuclear neutrophil and antisalmonella antibody must act together to effect neutrophil-associated bactericidal activity against virulent salmonellae, and thus, that the neutrophil alone does not play a major role in the protection of unvaccinated, sensitive mice from disease caused by S. typhimurium.

View details for Web of Science ID A1984TU45000010

View details for PubMedID 6391643
Biochemical and polyacrylamide gel electrophoretic analyses of vaginosis-associated anaerobic curved rods. Scandinavian journal of urology and nephrology. Supplementum Baron, E. J., Wexler, H. M., Finegold, S. M. 1984; 86: 65-69
Abstract

Morphologic, biochemical, and sodium-dodecyl sulfate polyacrylamide gel electrophoresis characteristics of twenty-six anaerobic curved rods isolated from vaginal discharge or transcervical uterine cultures were compared with each other and with those of five known control strains of anaerobic bacilli. The curved rods could be divided into two distinct groups, based on shared morphological characteristics and similar patterns of major cell protein bands. The protein band pattern exhibited by Group I organisms, which were short, Gram-variable, comma-shaped bacilli, did not resemble the protein band pattern of Group II organisms, which were seen as long, thin, Gram-negative curved rods. Polyacrylamide gel electrophoretic analysis of protein band patterns of these curved rods failed to show any strong similarities to the patterns of the five known bacterial strains that were tested. Although the role of these organisms in the etiology of bacterial vaginosis is not known at present, characterization studies such as this should facilitate the further recognition and identification of these bacilli as a prerequisite to determining their significance in human infection.

View details for PubMedID 6598924
ELICITATION OF PERITONEAL POLYMORPHONUCLEAR NEUTROPHILS FROM MICE JOURNAL OF IMMUNOLOGICAL METHODS Baron, E. J., PROCTOR, R. A. 1982; 49 (3): 305-313
Abstract

Although the mouse has been used extensively as a model for the study of host-parasite relationships, murine neutrophils have not been used nearly as often as PMNs from other species for in vitro functional assays due to lack of a commonly used procedure for murine neutrophil collection. These studies compared two eliciting agents and characterized the phagocytic and bactericidal activity of murine polymorphonuclear neutrophils elicited from the peritoneal cavity. We examined the effects of mouse strain (BALB/c, C57BL/6 and DBA/2) and sex, eliciting agent (0.2% glycogen vs. 3% fluid thioglycolate medium) and donor sacrifice method (ether vs. cervical dislocation) on the number of neutrophils recovered in peritoneal exudate. The greatest number of neutrophils was harvested when mice were sacrificed 5 h after intraperitoneal injection of 2.5 ml of 3% thioglycolate medium. This method as described allows reproducible collection of adequate numbers of neutrophils for use in in vitro assays of neutrophils phagocytic and bactericidal function.

View details for Web of Science ID A1982NG02200008

View details for PubMedID 7040554
ACTINOMYCOTIC PULMONARY ABSCESS IN AN IMMUNOSUPPRESSED PATIENT AMERICAN JOURNAL OF CLINICAL PATHOLOGY Baron, E. J., ANGEVINE, J. M., SUNDSTROM, W. 1979; 72 (4): 637-639
Abstract

The clinical history of a patient with rheumatoid arthritis and bacteriologic findings from a pulmonary abscess occurring during prednisone therapy are presented. Direct transthoracic aspiration of the lesion yielded a pure culture of Actinomyces odontolyticus. This is believed to be the first case of a deep visceral infection with this organism, an inhabitant of the normal mouth and gums. Immunosuppression of the host probably played a role in establishment of the infection.

View details for Web of Science ID A1979HS05000025

View details for PubMedID 495569
PRIMARY PLATE IDENTIFICATION OF GROUP-A BETA-HEMOLYTIC STREPTOCOCCI UTILIZING A 2-DISK TECHNIQUE JOURNAL OF CLINICAL MICROBIOLOGY Baron, E. J., GATES, J. W. 1979; 10 (1): 80-84
Abstract

A two-disk system is described which allows primary plate identification of group A beta-hemolytic streptococci. Group A beta-hemolytic streptococci could be visualized on primary throat culture plates by using trimethoprim-sulfamethoxazole to inhibit normal flora. In the heavily inoculated area of Trypticase soy agar plates containing 5% sheep blood, a 25-microgram/ml trimethoprim-sulfamethoxazole disk was placed contiguous to a 0.04-U bacitracin disk. A total of 259 throat specimens were examined with this two-disk system. The swabs from these throat specimens were incubated in Todd-Hewitt broth. The bacterial pellet from the broths was stained by fluorescent antibody as a control. Of the cultures that were determined to be positive on the plates, 75% could be read unequivocally after overnight incubation, whereas the remaining 25% required subculture. The plates recovered 91% of the cultures which were considered as true positives by the broth-fluorescent-antibody technique. This method provided a significant savings in time compared with standard plate methods and in cost of materials compared with broth-fluorescent-antibody methods. This technique is particularly valuable for producing rapid results in laboratories where fluorescence microscopy would not be cost-effective.

View details for Web of Science ID A1979HC26100016

View details for PubMedID 387811

Professor of Pathology at the Stanford University Medical Center, Emerita

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