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Journal of Pathogens
Volume 2017 (2017), Article ID 6738095, 5 pages
https://doi.org/10.1155/2017/6738095
Research Article

Molecular Epidemiology of Rifampicin Resistance in Mycobacterium tuberculosis Using the GeneXpert MTB/RIF Assay from a Rural Setting in India

1Department of Microbiology, Rural Development Trust Hospital, Bathalapalli, Andhra Pradesh, India
2Department of Infectious Diseases, Rural Development Trust Hospital, Bathalapalli, Andhra Pradesh, India

Correspondence should be addressed to Gerardo Alvarez-Uria

Received 29 August 2017; Revised 28 September 2017; Accepted 11 October 2017; Published 26 October 2017

Academic Editor: James Chambers

Copyright © 2017 Raghuprakash Reddy and Gerardo Alvarez-Uria. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Xpert MTB/RIF assay can detect mutations in rpoB gene that confer rifampicin resistance (RR) using five overlapping probes (A, B, C, D, and E). In this study, we described our experience with the Xpert assay in a rural setting in India. During the study period, 3250 samples were processed. The result was unsuccessful in 5.7% of cases. For extrapulmonary specimens, the risk of unsuccessful result was higher in tissue biopsy and stool samples. Among samples positive for Mycobacterium tuberculosis, rifampicin resistance was indeterminate in 1.2% of them. Our results and a review of the literature showed that the most frequent mutations conferring RR were located in the region of Probe E (63.6%; 95% confidence interval [CI] 56.26–70.94), followed by Probe B (15.02%; 95% CI 11.94–18.10), Probe D (13.35%; 95% CI 10.01–16.69), Probe A (4.73%; 95% CI 1.92–7.54), and Probe C (1.61%; 95% CI 0.67–2.54). Although the high cost of the cartridges precluded using the Xpert assay for routine diagnosis of tuberculosis, our results demonstrate that the assay can be used to diagnose RR-tuberculosis in rural areas with limited laboratory infrastructure and could be a convenient tool to investigate the molecular epidemiology of RR in resource-limited settings.