Clinical Evaluation of the Xpert MTB/XDR Assay for Rapid Susceptibility Testing of Mycobacterium tuberculosis in a Region of High TB Burden

Abstract

Background: Drug-resistant tuberculosis (DR-TB) poses a significant threat to TB control programs in Pakistan. Conventional drug susceptibility testing (DST) methods are slow and technically demanding, leading to delays in appropriate treatment. Rapid molecular tests like the Xpert MTB/XDR are crucial for timely diagnosis and improving patient outcomes in high-burden settings like Peshawar. Objective: To evaluate the diagnostic accuracy of the Xpert MTB/XDR test for the detection of resistance to first- and second-line anti-tuberculosis drugs in Peshawar, Pakistan. Methodology: This study was a cross-sectional, blinded, lab-based inquiry that used culture isolates or sputum samples. The Xpert® MTB/XDR test's diagnosis accuracy was compared to that of the MGIT960, the reference drug susceptibility testing (DST) techniques, and the Hain Genotype® MTBDR plus and MDRsl assays (LPA). Results: The patients were divided into three groups based on technique used i.e., Pre-LPA or DST, Post-LPA and Ten color Xpert MTB/XDR and followed up for their culture conversion. In this study,180 positive MDR-TB patients were included. Gene-Xpert MTB/RIF showed 93% cases were positive and on DST all cases showed positive results. For Drug-resistance in DST, LPA and Gene-Xpert MTB/XDR, 61.1% patients were resistant to three first-line drugs and 11.1% resistant to second line. Conclusion: This study concludes that based on timely initiation of treatment and culture conversion reports, DST and LPA are less efficient than Ten-color Gene Xpert MTB/XDR assay.