Evaluation of GenoType® MTBDRplus assay for rapid detection of drug susceptibility testing of multi-drug resistance tuberculosis in Northern India

Background: The problem of multi-drug resistance tuberculosis (MDR-TB) is growing in several hotspots throughout the world. Rapid and accurate diagnosis of MDR-TB is crucial to facilitate early treatment and to reduce its spread in the community. The aim of the present study was to evaluate the new, novel GenoType (R) MTBDRplus assay for rapid detection of drug susceptibility testing (DST) of MDR-TB cases in Northern India. Materials and Methods: A total of 550 specimens were collected from highly suspected drug resistant from pulmonary and extra-pulmonary TB cases. All the specimens were processed by ZiehlNeelsen staining, culture, differentiation by the GenoType (R) CM assay, fi rst line DST using BacT/ALERT 3D system and GenoType (R) MTBDRplus assay. The concordance of the GenoType (R) MTBDRplus assay was calculated in comparison with conventional DST results. Results: Overall the sensitivity for detection of rifampicin, isoniazid and MDR-TB resistance by GenoType (R) MTBDRplus assay was 98.0%, 98.4% and 98.2% respectively. Out of 55 MDR-TB strains, 45 (81.8%), 52 (94.5%) and 17 (30.9%) strains showed mutation in rpoB, katG and inhA genes respectively (P < 0.05). The most prominent mutations in rpoB, katG and inhA genes were; 37 (67.3%) in S531L, 52 (94.5%) in S315T1 and 11 (20%) in C15T regions respectively (P < 0.05). Conclusions: Our study demonstrated a high concordance between the GenoType (R) MTBDRplus assay resistance patterns and those were observed by conventional DST with good sensitivity, specifi city with short turnaround times and to control new cases of MDR-TB in countries with a high prevalence of MDR-TB.