Original Research ARTICLE
Evaluation of Genotype MTBDRplus and MTBDRsl assays for rapid detection of drug resistance in extensively drug-resistant Mycobacterium tuberculosis isolates in Pakistan
- 1Department of Microbiology and Molecular Genetics, University of the Punjab, Pakistan
- 2Department of Applied Microbiology, Faculty of Biology, University of Warsaw, Poland
- 3Provincial Tuberculosis Control Program , Punjab, Pakistan
Pakistan ranks 5th among the world’s highest tuberculosis (TB) burden countries alongside the 6th among countries with the highest burden of drug-resistant TB, including multi-drug resistant (MDR)-TB. Methods for rapid and reliable drug susceptibility testing are prerequisite for the prompt institution of effective anti-TB treatment. The aim of this study was to evaluate the efficiency of Genotype MTBDRplus and MTBDRsl assays for the detection of MDR and (pre-)extensively drug-resistant (XDR-TB) isolates in Pakistan.
The study included 47 pre-XDR and 6 XDR-TB isolates, recovered from as many patients from Pakistan. Conventional drug susceptibility testing was performed using the standard 1% proportion method on the Löwenstein-Jensen medium. For molecular determination of drug resistance, GenoType MTBDRplus and GenoType MTBDRsl assays (Hain Lifescience, Germany) were used. To evaluate discrepancies between conventional and molecular DST results, mutation profiling was performed by amplifying and sequencing seven genetic loci, i.e. katG, inhA, and mabA-inhA promoter, rpoB, gyrA, embB, rrs.
The sensitivity of Genotype MTBDRplus was 71.7% for INH and 79.2% for RIF. Sequence analysis revealed non-synonymous mutations in 93.3% and 27.3% of isolates phenotypically resistant to INH and RIF, respectively, albeit susceptible when tested by GenoType MTBDRplus. GenoType MTBDRsl had a sensitivity of 73.6%, 64.7%, 20%, 25%, and 100% for the detection of fluoroquinolones, ethambutol, kanamycin, amikacin, and capreomycin resistance, respectively. Upon sequencing, mutations were detected in 20%, 77.8%, and all isolates phenotypically resistant to aminoglycosides, ethambutol, and fluoroquinolones, respectively, yet. declared as susceptible with GenoType MTBDRsl.
Low sensitivities seriously impedes the large-scale application of the Genotype MTBDRplus and MTBDRsl assays. Unless further optimized, the currently available line-probe assays should rather be auxiliary to the conventional, phenotype-based methods in the detection of MDR- and XDR-TB in Pakistan.
Keywords: Genotype MTBDRplus, Genotype MTBDRsl, Line probe assay, Mycobacterium tuberculosis, Drug Resistance
Received: 26 Feb 2018;
Accepted: 05 Sep 2018.
Edited by:Xiao-Yong Fan, Fudan University, China
Reviewed by:Gurvinder Kaur, Laboratory Oncology, All India Institute of Medical Sciences, India
Jianping Xie, Southwest University, China
Jason Sahl, Northern Arizona University, United States
Copyright: © 2018 Javed, Bakuła, Pleń, Hashmi, Tahir, Jamil and Jagielski. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Tomasz Jagielski, Faculty of Biology, University of Warsaw, Department of Applied Microbiology, Warsaw, 02-096, Poland, email@example.com