Recovery rate of NTM from AFB smear-positive sputum specimens at a medical centre in South Korea

OBJECTIVE: To investigate the recovery rate of non-tuberculous mycobacteria (NTM) from acid-fast bacilli (AFB) smear-positive sputum specimens at a tertiary care medical centre in South Korea with a high pulmonary tuberculosis (PTB) burden. DESIGN: Retrospective analysis of data from AFB smear- and culture-positive sputum specimens collected between January 1998 and December 2001. RESULTS: Over 4 years, 1328 sputum specimens collected from 616 patients were AFB smear- and culture-positive. NTM were recovered from 9.1% (121/1328) of the smear-positive sputum specimens, and from 8.1% (50/616) of patients with smear-positive sputum. NTM were isolated at least twice in 94% (47/50) of the patients from whom NTM was recovered. The most common organism found was Mycobacterium avium complex, followed by M. abscessus. CONCLUSION: These results suggest that a substantial proportion of patients at a tertiary care medical centre in South Korea with AFB smear-positive sputum specimens may have NTM lung disease rather than PTB.