Whole Genome Sequencing Investigation of a Tuberculosis Outbreak in Port-au-Prince, Haiti Caused by a Strain with a "Low-Level" rpoB Mutation L511P - Insights into a Mechanism of Resistance Escalation.
2015; 10 (6)
CD4 deficit and tuberculosis risk persist with delayed antiretroviral therapy: 5-year data from CIPRA HT-001.
international journal of tuberculosis and lung disease
2015; 19 (1): 50-57
The World Health Organization recommends diagnosing Multidrug-Resistant Tuberculosis (MDR-TB) in high burden countries by detection of mutations in Rifampin (RIF) Resistance Determining Region of Mycobacterium tuberculosis rpoB gene with rapid molecular tests GeneXpert MTB/RIF and Hain MTBDRplus. Such mutations are found in >95% of Mycobacterium tuberculosis strains resistant to RIF by conventional culture-based drug susceptibility testing (DST). However routine diagnostic screening with molecular tests uncovered specific "low level" rpoB mutations conferring resistance to RIF below the critical concentration of 1 μg/ml in some phenotypically susceptible strains. Cases with discrepant phenotypic (susceptible) and genotypic (resistant) results for resistance to RIF account for at least 10% of resistant diagnoses by molecular tests and urgently require new guidelines to inform therapeutic decision making. Eight strains with a "low level" rpoB mutation L511P were isolated by GHESKIO laboratory between 2008 and 2012 from 6 HIV-negative and 2 HIV-positive patients during routine molecular testing. Five isolates with a single L511P mutation and two isolates with double mutation L511P&M515T had MICs for RIF between 0.125 and 0.5 μg/ml and tested susceptible in culture-based DST. The eighth isolate carried a double mutation L511P&D516C and was phenotypically resistant to RIF. All eight strains shared the same spoligotype SIT 53 commonly found in Haiti but classic epidemiological investigation failed to uncover direct contacts between the patients. Whole Genome Sequencing (WGS) revealed that L511P cluster isolates resulted from a clonal expansion of an ancestral strain resistant to Isoniazid and to a very low level of RIF. Under the selective pressure of RIF-based therapy the strain acquired mutation in the M306 codon of embB followed by secondary mutations in rpoB and escalation of resistance level. This scenario highlights the importance of subcritical resistance to RIF for both clinical management of patients and public health and provides support for introducing rpoB mutations as proxy for MICs into laboratory diagnosis of RIF resistance. This study illustrates that WGS is a promising multi-purpose genotyping tool for high-burden settings as it provides both "gold standard" sequencing results for prediction of drug susceptibility and a high-resolution data for epidemiological investigation in a single assay.
View details for DOI 10.1371/journal.pone.0129207
View details for PubMedID 26039194
Tuberculosis in the aftermath of the 2010 earthquake in Haiti
Bulletin of the World Health Organization
2015; 93 (7): 436-512
Gender inequality and HIV transmission: a global analysis
JOURNAL OF THE INTERNATIONAL AIDS SOCIETY
Correlation between Genotypic and Phenotypic Testing for Resistance to Rifampin in Mycobacterium tuberculosis Clinical Isolates in Haiti: Investigation of Cases with Discrepant Susceptibility Results
2014; 9 (3)
Port-au-Prince, Haiti.To determine long-term effects of early vs. delayed initiation of antiretroviral therapy (ART) on immune recovery and tuberculosis (TB) risk in human immunodeficiency virus (HIV) infected individuals.Open-label randomized controlled trial of immediate ART in HIV-infected adults with CD4 counts between 200 and 350 cells/mm(3) vs. deferring ART until the CD4 count was <200 cells/mm(3). The primary comparisons were CD4 counts over time and risk for incident TB, with 5 years of follow-up.A total of 816 participants were enrolled, with 408 in each treatment arm. The early treatment group started ART within 2 weeks, while the deferred treatment group started ART a median of 1.3 years after enrollment. After 5 years, the mean CD4 count in the early treatment group was significantly higher than in the deferred treatment group (496 cells/mm(3), 95% confidence interval [CI] 477-515 vs. 373 cells/mm(3), 95%CI 357-389; P < 0.0001). TB risk was higher in the deferred treatment group (unadjusted HR 2.41, 95%CI 1.56-3.74; P < 0.0001) and strongly correlated with lower CD4 counts in time-dependent multivariate analysis.Delays in ART initiation for HIV-infected adults with CD4 counts of 200-350 cells/mm(3) can result in long-term immune dysfunction and persistent increased risk for TB.
View details for DOI 10.5588/ijtld.14.0217
View details for PubMedID 25519790
Integrating integrase inhibitors into an antiretroviral regimen
CURRENT TREATMENT OPTIONS IN INFECTIOUS DISEASES
2014; 6 (2)
Outcomes of HIV-infected patients treated for recurrent tuberculosis with the standard retreatment regimen
INTERNATIONAL JOURNAL OF TUBERCULOSIS AND LUNG DISEASE
2012; 16 (6): 841-845
The World Health Organization has recommended use of molecular-based tests MTBDRplus and GeneXpert MTB/RIF to diagnose multidrug-resistant tuberculosis in developing and high-burden countries. Both tests are based on detection of mutations in the Rifampin (RIF) Resistance-Determining Region of DNA-dependent RNA Polymerase gene (rpoB). Such mutations are found in 95-98% of Mycobacterium tuberculosis strains determined to be RIF-resistant by the "gold standard" culture-based drug susceptibility testing (DST). We report the phenotypic and genotypic characterization of 153 consecutive clinical Mycobacterium tuberculosis strains diagnosed as RIF-resistant by molecular tests in our laboratory in Port-au-Prince, Haiti. 133 isolates (86.9%) were resistant to both RIF and Isoniazid and 4 isolates (2.6%) were RIF mono-resistant in MGIT SIRE liquid culture-based DST. However the remaining 16 isolates (10.5%) tested RIF-sensitive by the assay. Five strains with discordant genotypic and phenotypic susceptibility results had RIF minimal inhibitory concentration (MIC) close to the cut-off value of 1 µg/ml used in phenotypic susceptibility assays and were confirmed as resistant by DST on solid media. Nine strains had sub-critical RIF MICs ranging from 0.063 to 0.5 µg/ml. Finally two strains were pan-susceptible and harbored a silent rpoB mutation. Our data indicate that not only detection of the presence but also identification of the nature of rpoB mutation is needed to accurately diagnose resistance to RIF in Mycobacterium tuberculosis. Observed clinical significance of low-level resistance to RIF supports the re-evaluation of the present critical concentration of the drug used in culture-based DST assays.
View details for DOI 10.1371/journal.pone.0090569
View details for Web of Science ID 000332479400094
View details for PubMedID 24599230
High Mortality among Patients with AIDS Who Received a Diagnosis of Tuberculosis in the First 3 Months of Antiretroviral Therapy
CLINICAL INFECTIOUS DISEASES
2009; 48 (6): 829-831
The Groupe Haitien d'Etude du Sarcome de Kaposi et des Infections Opportunistes (the GHESKIO AIDS and TB Center) in Port-au-Prince, Haiti.To measure the effectiveness of the standard TB retreatment regimen (2HRZES/1HRZE/5HRE) in human immunodeficiency virus (HIV) infected adults.Cohort study.Of 1318 HIV-infected patients with access to antiretroviral therapy following World Health Organization guidelines, 56 were diagnosed with recurrent pulmonary TB and retreated with the standard retreatment regimen: 10 patients (18%) died during retreatment, 3 (5%) defaulted, and 2 (4%) failed treatment. Forty-one patients (73%) achieved retreatment 'success' (cure, treatment completed). Of these, 8 (20%) died during follow-up, 5 (12%) were lost, and 5 (12%) had a second recurrence of TB. Only 26 (46%) of the 56 patients remained alive, in care, and TB-free after a median of 36 months of follow-up.HIV-infected patients treated for recurrent TB with the standard retreatment regimen have high mortality and poor long-term outcomes.
View details for DOI 10.5588/ijtld.11.0210
View details for Web of Science ID 000304580400024
View details for PubMedID 22507948
We analyzed mortality among 201 patients with AIDS and tuberculosis in Haiti. Patients who received a diagnosis of tuberculosis during the first 3 months after the initiation of antiretroviral therapy were 3.25 times more likely to die than were other patients with AIDS and tuberculosis. Failure to recognize active tuberculosis at initiation of antiretroviral therapy leads to increased mortality.
View details for DOI 10.1086/597098
View details for Web of Science ID 000263949000022
View details for PubMedID 19207078