Validation of the GenoType® MTBDRplus Ver 2.0 assay for detection of rifampicin and isoniazid resistance in Mycobacterium tuberculosis complex isolates at UZCHS-CTRC TB research laboratory.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) is a public health concern globally. MDR-TB is defined as resistance to rifampicin (RIF) and isoniazid (INH), the two-major anti-TB first-line TB treatment drugs. Rapid identification of MDR-TB can contribute significantly to the control of TB. The GenoType® MTBDRplus Ver 2.0 assay is a molecular assay used to detect genetic mutations that result in RIF and INH resistance. The aim of this study was to validate the performance of the GenoType® MTBDRplus Ver 2.0 assay for the detection of INH and RIF resistance. METHODS: Fifty-five stored Mycobacterium tuberculosis isolates were tested using both the mycobacterial growth indicator tube (MGIT), antimicrobial susceptibility testing (AST), and the GenoType® MTBDRplus Ver 2.0 assay. The MGIT AST was done according to the BBL MGIT AST SIRE system with RIF and INH final critical concentrations of 1.0 µg/ml and 0.1 µg/ml, respectively. The GenoType® MTBDRplus assay (Hain Lifescience, Germany) was performed following the manufacturer's instructions. RESULTS: The GenoType® MTBDRplus Ver 2.0 assay had a sensitivity, specificity, positive predictive value, and negative predictive value of 100% for INH and RIF resistance. The intra-assay precision for the assay was 100%. CONCLUSION: The GenoType® MTBDRplus Ver 2.0 assay's sensitivity and specificity show that the assay is highly accurate for the detection of RIF and INH resistance and thus can be used as an alternate platform due to its shorter results turnaround time.

The Etiology of Vaginal Discharge Syndrome in Zimbabwe: Results from the Zimbabwe STI Etiology Study.

INTRODUCTION: Symptomatic vaginal discharge is a common gynecological condition managed syndromically in most developing countries. In Zimbabwe, women presenting with symptomatic vaginal discharge are treated with empirical regimens that commonly cover both sexually transmitted infections (STIs) and reproductive tract infections, typically including a combination of an intramuscular injection of kanamycin, and oral doxycycline and metronidazole regimens. This study was conducted to determine the current etiology of symptomatic vaginal discharge and assess adequacy of current syndromic management guidelines. METHODS: We enrolled 200 women with symptomatic vaginal discharge presenting at 6 STI clinics in Zimbabwe. Microscopy was used to detect bacterial vaginosis and yeast infection. Nucleic acid amplifications tests were used to detect Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, and Mycoplasma genitalium. In addition, serologic testing was performed to detect human immunodeficiency virus (HIV) infection. RESULTS: Of the 200 women, 146 (73%) had an etiology detected, including bacterial vaginosis (24.7%); N. gonorrhoeae (24.0%); yeast infection (20.7%); T. vaginalis (19.0%); C. trachomatis (14.0%) and M. genitalium (7.0%). Among women with STIs (N = 90), 62 (68.9%) had a single infection, 18 (20.0%) had a dual infection, and 10 (11.1%) had 3 infections.Of 158 women who consented to HIV testing, 64 (40.5%) were HIV infected.The syndromic management regimen covered 115 (57.5%) of the women in the sample who had gonorrhea, chlamydia, M. genitalium, or bacterial vaginosis, whereas 85 (42.5%) of women were treated without such diagnosis. CONCLUSIONS: Among women presenting with symptomatic vaginal discharge, bacterial vaginosis was the most common etiology, and gonorrhea was the most frequently detected STI. The current syndromic management algorithm is suboptimal for coverage of women presenting with symptomatic vaginal discharge; addition of point of care testing could compliment the effectiveness of the syndromic approach.