Isolation, characterization and determination of drug susceptibility pattern of mycobacterial isolates from newly diagnosed cases – a study from a tertiary care centre in South India

Tuberculosis continues to be an important public health problem in India and globally. Drug resistance, especially multi-drug resistance to antituberculous drugs and co-infection of human immunodeficiency virus with mycobacteria are the two most important hurdles in the management of tuberculosis. In this study, we isolated and identified mycobacteria from clinical specimens of patients with tuberculosis using conventional methods and tested their drug susceptibility using the proportion method on Lowenstein-Jensen (LJ) medium. Of the 100 mycobacterial isolates from newly diagnosed cases, 3% were non tuberculous mycobacteria (NTM). Among the isolates of Mycobacterium tuberculosis, primary drug resistance to isoniazid and rifampicin were 5.2% and 2.1% respectively. The initial anti tuberculosis drug resistance in this study is low and more studies with larger sample size are needed in future to ascertain the true prevalence of drug resistance.