Drug resistance patterns and treatment outcomes in DR-TB patients at a tertiary care centre in Mumbai

Abstract

BackgroundDrug-resistant tuberculosis (DR-TB) is a major health problem and threatens Tuberculosis (TB) control and outcomes globally. India holds one-fourth of global DR-TB burden.1 Aims1- To study drug resistance patterns and outcomes in DR-TB patients under National Tuberculosis Elimination Programme (NTEP) at a tertiary care-centre. 2- To correlate outcome of DR-TB with drug resistance patterns. MethodsIt is a retrospective study of 302 Drug Resistant Tuberculosis patients from Jan 2020 to May 2022. Common mutations of drug resistance, pyrazinamide resistance in DR-TB patients, correlation of High dose Moxifloxacin sensitivity by Line Probe Assay (LPA) and drug sensitivity test (DST), outcome of DR-TB patients with drug resistance patterns and correlation of outcome of DR-TB patients with their initial body-weight were studied. ResultsKat G was the most common mutation in Isoniazid (96%) resistance for MDR TB as well as Isoniazid Mono-resistance TB (p = 0.001). 91% cases with MDR-TB were resistant to pyrazinamide. 51.2% cases had low dose Fluroquinolone resistance. 18.8% cases had low and high dose Fluroquinolone resistance. 8.5% cases had resistance to injectables. 21.7% of cases who were resistant to High dose Moxifloxacin on second line LPA were found to be sensitive on DST. Outcomes were not dependent on the LPA resistance patterns. Body-weight greater than 45 Kg at the time of initiation of treatment was associated with better outcomes (p = 0.007). ConclusionDR-TB patients are resistant to pyrazinamide in nearly all cases; hence pyrazinamide is not suitable for initial replacement sequence. Second line resistance doesn't impact outcome in DR-TB patients.