Prevalence of atypical mycobacteria in sputum of patients undergoing treatment at a tuberculosis clinic.

A total of 4,554 sputum specimens of 3,943 patients were examined with a view to isolate atypical mycobacteria. Of these 604 (13.3%) specimens were culture positive for AFB, out of which 48 cultures (7.9%) from 47 patients were identified as atypical mycobacteria. Two patients were considered as probable cases of atypical mycobacterial disease while in the remaining 45 patients, atypical mycobacteria appeared to colonize the lungs without producing any disease.