Colorimetric Redox Indicator assay for rapid detection of multidrug-resistant Mycobacterium tuberculosis in South Gujarat region

Singh Shruti S.; Desai Pratibha B.

doi:10.37591/rrjomv.v8i3.343

Abstract

Tuberculosis (TB) has affected humans since antiquity. The burden of TB particularly with multi-drug-resistance (MDR) is increasing worldwide and has become a major public health concern. This study aims to perform Colorimetric Redox Indicator (CRI) assay for rapid detection of multidrug-resistant Mycobacterium tuberculosis in South Gujarat region. Total 234 samples were collected from South Gujarat region and were subjected for microscopy examination, culturing on Lowenstein-Jensen (LJ) medium and drug susceptibility testing by indirect CRI. Indirect CRI was performed on the culture isolates and the performance was evaluated and compared to that of the Conventional LJ Proportion Method. In our study, 4.95% and 14.85% samples were found to be RIF-Monoresistant and INH-Monoresistant respectively. 34.65% samples were detected as MDR. Majority of resistant strains had an MIC≥1 μg/ml for INH and MIC 1 μg/ml for RIF. While, most susceptible strains had an MIC≤0.031 μg/ml for INH and MIC≤0.062 μg/ml for RIF. As compared to Proportion method, the sensitivity and specificity by CRI for RIF were 62.5% and 100% respectively while for INH, the sensitivity and specificity were 100% and 93.47% respectively. In conclusion, the CRI assay appears to be simple, cheap and rapid method for detection of multidrug-resistant Mycobacterium tuberculosis, especially in poor-resource countries, with limited laboratory facilities. The technique may become a valid substitute to traditional time-consuming methods.Keywords: M. tuberculosis, colorimetric redox indicator assay, minimal inhibitory concentration evaluation, multidrug-resistanceCite this ArticleSingh Shruti S., Desai Pratibha B. Colorimetric Redox Indicator assay for rapid detection of multidrug-resistant Mycobacterium tuberculosis in South Gujarat region. Research & Reviews: A Journal of Microbiology and Virology. 2018; 8(3): 65–70p.