Study of prevalence of drug resistance in tuberculosis (TB) patients attending a tertiary care hospital at Mumbai

Abstract

Introduction: RNTCP estimates MDR in India as 2-3% in new and 12-17% in treated cases. Mumbai is a hot spot for TB drug resistance in India. A prior study evaluating MDR patients revealed 29.4% MDR, 56.8% pre XDR, 10.6% XDR and 5.6% XXDR in Mumbai. Aims & objectives: To evaluate the patterns of drug resistance in TB patients following up at our hospital. Methods: A retrospective observational study of drug susceptibility testing (DST) results on positive TB MGIT cultures of 53 TB patients from January 2015 to December 2015) was conducted. Patients were classified into 5 categories based on the DST results as drug sensitive TB, MDR TB, pre XDR TB, XDR TB & XXDR TB. Results: 43 patients (81.13%) had pulmonary and 10 patients (18.87%) had extra-pulmonary TB. Of the 43 pulmonary cases, 18(41.86%) had drug sensitive TB and 25(58.13%) had drug resistant TB. In drug resistant pulmonary cases, pre XDR TB was found in 15(60%), MDR TB in 6(24%), XXDR TB in 2(8%), XDR TB in 1(4%) and INH mono resistance in 1(4%). Amongst 10 extra-pulmonary TB cases, 4(40%) had drug sensitive TB and 6(60%) had drug resistant TB of which pre XDR TB was found in 4(66.66%), XXDR in 1(16.66%) and INH mono resistance in 1(16.66%). Overall incidence of pre-XDR TB was 61.9% (19 Patients). Conclusion: Incidence of pre XDR TB is on the rise among drug resistant pulmonary and extra-pulmonary TB patients in Mumbai. This necessitates the need for complete drug susceptibility testing and not relying solely on molecular techniques that will identify MDR only. Individualized drug regimens for these patients based on DST will help in curtailing transmission of resistant strains within the community.