Prevalence of non-tuberculous mycobacterium in a tertiary care hospital from South India.

Tuberculosis is a wide spread infectious disease all over the world as well as in India. Other than tuberculosis complex, more than 30 different non-tuberculous mycobacteria (NTM) are responsible for various diseases, i.e. cervical lymphadelopathy, cutaneous abscess, pulmonary diseases, post-operative infections, etc. These NTMs are resistant to commonly used antimicrobial and anti-tubercular agents, jeopardizing the DOTS and DOTS PLUS program in the country. The accurate diagnosis of mycobacteria upto species level is an urgent need to check/control the increasing incidence of tuberculosis in community. A total of 3456 pulmonary and extra-pulmonary samples were subjected to smear examination and culture. The cultures were done in duplicate using Lowenstein Jensen media and examine weekly upto 8 weeks. A total of 33 positive cultures were identified by growth rate, pigment production, niacin test, nitrate test, heat stable catalase test, semiquantitative catalase test, tellurit reduction test, urease test, tween 80 hydrolysis, growth on McConkey media, growth in 5% sodium chloride and susceptibility to para-nitro benzoic acid. The results showed 33.33% were mycobacterium tuberculosis complex and 66.66% were non-tuberculosis mycobacterium. Among the non-tuberculous group, 11 different species of mycobacteria were identified during this study. Identification of mycobacteria is an utmost necessity in every big hospital as it helps clinicians to treat and stop further spread of the disease tuberculosis. This study reveals that NTM are the major group in culture positive pulmonary and extrapulmonary tuberculosis. The importance of NTM can be further evaluated by conducting more studies and need active participation of reference laboratories.