Drug susceptibility testing and line probe assay of first-line anti-tuberculosis drugs among presumptive tuberculosis patients attending a secondary care hospital in Bhubaneswar

Abstract

ABSTRACT Background: Pyrazinamide (PZA) is important for identification in multi-drug-resistant tuberculosis patients before starting therapy. PZA drug susceptibility testing (DST) is essential for the management of drug-resistant and susceptible TB patients. Aims: The degree of drug resistance among TB patients and discrepancy between DST results of the phenotype and genotype were assessed. Materials and Methods: Socio-demographic and clinical profiles of TB patients recruited in the study were documented. Sputum samples were processed for diagnosis using TrueNat Xpert MTB, TrueNat Xpert MTB Plus, and MGIT culture. Results: Rifampicin (RIF) line probe assay (LPA) showed the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100%, whereas isoniazid (INH) LPA testing showed a sensitivity of 85.7%, a specificity and PPV of 100%, and NPV of 94.8%. The gene mutation for RIF resistance was between the codon, 530–533 of rpoB gene, and that for INH resistance was at the codon, 315 of katG gene. Conclusion: Our findings demonstrated high prevalence of mono- and poly-drug resistance as well as pyrazinamide resistance.