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| ORIGINAL ARTICLE |
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| Year : 2013 | Volume
: 59
| Issue : 3 | Page : 179-185 |
Rapid detection of drug resistance and mutational patterns of extensively drug-resistant strains by a novel GenoType® MTBDRsl assay
AK Singh1, AK Maurya2, S Kant3, J Umrao1, RAS Kushwaha3, VL Nag1, TN Dhole1
1 Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
2 Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences; Department of Pulmonary Medicine, King George Medical University, Lucknow, Uttar Pradesh, India
3 Department of Pulmonary Medicine, King George Medical University, Lucknow, Uttar Pradesh, India
Correspondence Address:
T N Dhole
Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh
India
 Source of Support: Indian Council of Medical Research, New Delhi, India,
(Extramural ICMR Project Sanction No. 5/8/5/4/2007.ECD.I), Conflict of Interest: None  | Check |
DOI: 10.4103/0022-3859.118034
Background: The emergence of extensively drug-resistant tuberculosis (XDR-TB) is a major concern in the India. The burden of XDR-TB is increasing due to inadequate monitoring, lack of proper diagnosis, and treatment. The GenoType ® Mycobacterium tuberculosis drug resistance second line (MTBDRsl) assay is a novel line probe assay used for the rapid detection of mutational patterns conferring resistance to XDR-TB. Aim: The aim of this study was to study the rapid detection of drug resistance and mutational patterns of the XDR-TB by a novel GenoType ® MTBDRsl assay. Materials and Methods: We evaluated 98 multidrug-resistant (MDR) M. tuberculosis isolates for second line drugs susceptibility testing by 1% proportion method (BacT/ALERT 3D system) and GenoType ® MTBDRsl assay for rapid detection of conferring drug resistance to XDR-TB. Results: A total of seven (17.4%) were identified as XDR-TB by using standard phenotypic method. The concordance between phenotypic and GenoType ® MTBDRsl assay was 91.7-100% for different antibiotics. The sensitivity and specificity of the MTBDRsl assay were 100% and 100% for aminoglycosides; 100% and 100% for fluoroquinolones; 91.7% and 100% for ethambutol. The most frequent mutations and patterns were gyrA MUT1 (A90V) in seven (41.2%) and gyrA + WT1-3 + MUT1 in four (23.5%); rrs MUT1 (A1401G) in 11 (64.7%), and rrs WT1-2 + MUT1 in eight (47.1%); and embB MUT1B (M306V) in 11 (64.7%) strains. Conclusions: These data suggest that the GenoType ® MTBDRsl assay is rapid, novel test for detection of resistance to second line anti-tubercular drugs. This assay provides additional information about the frequency and mutational patterns responsible for XDR-TB resistance.
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