Use of GenoType® MTBDRplus assay to assess drug resistance and mutation patterns of multidrug-resistant tuberculosis isolates in northern India

Purpose: The emergence and spread of multidrug-resistant tuberculosis (MDR-TB) is a major public health problem. The diagnosis of MDR-TB is of paramount importance in establishing appropriate clinical management and infection control measures. The aim of this study was to evaluate drug resistance and mutational patterns in clinical isolates MDR-TB by GenoType (R) MTBDRplus assay. Material and Methods: A total of 350 non-repeated sputum specimens were collected from highly suspected drug-resistant pulmonary tuberculosis (PTB) cases; which were processed by microscopy, culture, differentiation and first line drug susceptibility testing (DST) using BacT/ALERT 3D system. Results: Among a total of 125 mycobacterium tuberculosis complex (MTBC) strains, readable results were obtained from 120 (96%) strains by GenoType (R) MTBDRplus assay. Only 45 MDR-TB isolates were analysed for the performance, frequency and mutational patterns by GenoType (R) MTBDRplus assay. The sensitivity of the GenoType (R) MDRTBplus assay for detecting individual resistance to rifampicin (RIF), isoniazid (INH) and multidrug resistance was found to be 95.8%, 96.3% and 97.7%, respectively. Mutation in codon S531L of the rpoB gene and codon S315T1 of katG genes were dominated in MDR-TB strains, respectively (P < 0.05). Conclusions: The GenoType (R) MTBDRplus assay is highly sensitive with short turnaround times and a rapid test for the detection of the most common mutations conferring resistance in MDR-TB strains that can readily be included in a routine laboratory workflow.