A NEWLY developed DNA biochip offers a promising solution for the rapid screening of second-line drug resistance (SLDR) in Mycobacterium tuberculosis, offering faster detection and improved accuracy for multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB). In a recently published study, the biochip demonstrated high sensitivity and specificity for identifying key mutations associated with resistance to fluoroquinolones (FQs) and second-line injectable drugs (SLIDs).
The rapid molecular technique leverages an in-house designed biochip to detect mutations in the gyrA, rrs, and eis genes, critical markers of resistance to FQs and SLIDs. This approach reduces the testing time for phenotypic drug susceptibility testing (DST) from several weeks to just one day, which is a significant breakthrough for TB control, especially in regions with high rates of MDR and XDR TB, such as India.
The study tested 112 M. tuberculosis clinical isolates, with results showing that 61% of the isolates were wild-type, while the remainder displayed mutations in the key resistance genes. The biochip’s sensitivity and specificity for detecting FQ resistance ranged from 75% to 100%, and for SLID resistance, it ranged from 90.9% to 100%, making it an accurate and reliable tool for detecting drug-resistant TB. The biochip was also capable of identifying mutations in the rrs and eis genes simultaneously, which is crucial for monitoring combined resistance patterns.
This breakthrough biochip not only holds great potential for improving clinical management but also offers valuable applications in epidemiological surveillance of TB. The development promises to expedite the identification of resistant strains, allowing for timely and appropriate treatment adjustments that could improve patient outcomes and contribute to better TB control efforts globally.
Reference:
Jain B. Rapid screening of mutations for second-line-drug-resistant genes in Mycobacterium tuberculosis culture isolates by in-house developed DNA bio-chip. Eur J Clin Microbiol Infect Dis. 2025. doi: 10.1007/s10096-025-05221-6.
