Species level identification of non-tuberculous mycobacteria from South Indian BCG trial area during 1981.

In 1981, non-tuberculous mycobacteria (NTM) were obtained from 8.6% of 16 907 sputum specimens in a trial in the Chingleput district of Madras state to test the efficacy of BCG vaccination in the prevention of tuberculosis, but from only 0.6% of 672 autoclaved specimens cultured as part of a quality control procedure. This finding suggested that the NTM were truly derived from the sputum of the BCG trial subjects. The mycobacterial species could be identified in 966 (96.6%) of the first 1000 isolates of NTM: 54.6% were potential pathogens and 73.0% were slow growing. The species isolated most frequently were M. avium/intracellulare (22.6% of all NTM), M. terrae (12.5%) and M. scrofulaceum (10.5%). Those species accounting for 8-5% of all NTM were M. fortuitum, M. chelonei, M. flavescens, M. gordonae and M. vaccae.