No abstract

BackgroundOver the past several years, new diagnostic techniques have been developed to allow for the rapid detection of multidrug resistant tuberculosis. The GenoType® MTBDRplus test is a deoxyribonucleic acid (DNA) strip assay which uses polymerase chain reaction (PCR) and hybridization to detect genetic mutations in the genes that confer isoniazid (INH) and rifampn (RIF) resistance. This assay has demonstrated good performance and a rapid time to results, making this a promising tool to accelerate MDR-TB diagnosis and improve MDR-TB control. Validation of rapid tests for MDR-TB detection in different settings is needed to ensure acceptable performance, particularly in Asia, which has the largest number of MDR-TB cases in the world but only one previous report, in Vietnam, about the performance of the GenoType® MDRplus assay. Thailand is ranked 18th of 22 "high-burden" TB countries in the world, and there is evidence to suggest that rates of MDR-TB are increasing in Thailand. We compared the performance of the GenoType® MTBDRplus assay to Mycobacterial Growth Indicator Tube for Antimycobacterial Susceptibility Testing (MGIT AST) for detection INH resistance, RIF resistance, and MDR-TB in stored acid-fast bacilli (AFB)-positive sputum specimens and isolates at a Public TB laboratory in Bangkok, Thailand.Methods50 stored isolates and 164 stored AFB-positive sputum specimens were tested using both the MGIT AST and the GenoType® MTBDRplus assay.ResultsThe GenoType® MTBDRplus assay had a sensitivity of 95.3%, 100%, and 94.4% for INH resistance, RIF resistance, and MDR-TB, respectively. The difference in sensitivity between sputum specimens (93%) and isolates (100%) for INH resistance was not statistically significant (p = 0.08). Specificity was 100% for all resistance patterns and for both specimens and isolates. The laboratory processing time was a median of 25 days for MGIT AST and 5 days for the GenoType® MTBDRplus (p < 0.01).ConclusionThe GenoType® MTBDRplus assay has been validated as a rapid and reliable first-line diagnostic test on AFB-positive sputum or MTB isolates for INH resistance, RIF resistance, and MDR-TB in Bangkok, Thailand. Further studies are needed to evaluate its impact on treatment outcome and the feasibility and cost associated with widespread implementation.

In Thailand, Capilia TB had acceptable sensitivity and specificity, was lower in cost and had shorter turn-around times. Laboratories investing in BBC should consider Capilia TB for identification of MTBC, after validation of performance in their setting.

HIV prevalence and associated risk behaviors were examined among Thai bisexually active men (MSMW, n = 450) and men who have sex with men only (MSM-only, n = 1,125). Cross sectional venue-day-time sampling was used to collect data. Chi-square and logistic regression were used to identify HIV risk factors. HIV prevalence was 8.2% among MSMW and 21.2% among MSM-only. Consistent condom use with male partners was higher among MSMW (77.6%) than MSM-only (62.9%), and lower with female partners (44.4%). Lack of family confidant, migration, concern about acquiring HIV infection, and self-reported STD were associated with HIV prevalence among MSMW. Older age, lower educational level, residing in Bangkok or Chiang Mai, living away from family, recruitment from a sauna, increased frequency of visiting the surveyed venue, practicing receptive or both receptive and insertive anal intercourse, inconsistent condom use with male paying partners, and a history of drug use were associated with HIV prevalence in MSM-only.