Acquired drug resistance pattern in tuberculosis cases at the State Tuberculosis Centre, Delhi, India

Abstract

Setting: State TB Demonstration Centre, Delhi, India.

Objective: To obtain a baseline estimate of the prevalence of multidrug-resistant tuberculosis (MDR-TB) among previously treated tuberculosis (TB) cases at the State Tuberculosis Centre in 2006.

Design: A retrospective study. Drug susceptibility data of 5252 previously treated patients tested at this centre were analysed.

Results: Of 2880 Mycobacterium tuberculosis isolates from previously treated cases, 1498 (52%) were resistant to one or more anti-tuberculosis drugs, of which 47.1% were MDR. Resistance to isoniazid was observed in all resistant isolates, followed by resistance to rifampicin in 1357 (47.1%), streptomycin in 403 (14.2%) and ethambutol in 107 (3.72%). A significantly higher rate of resistance, including MDR, was observed among treatment failures compared to relapses and defaulters.

Conclusion: A very high proportion of drug-resistant cases had MDR besides resistance to two or more drugs. This proportion was significantly higher among treatment failures compared to relapses and treatment after default cases, underlining the need for early identification of treatment failure by early referral for culture and drug susceptibility testing, and initiation of appropriate treatment.