Clinical features of non-tuberculous mycobacterial disease: comparisons between smear-positive and smear-negative cases, and between Mycobacterium avium and Mycobacterium intracellulare.

OBJECTIVE

To evaluate the differences in clinical symptoms and radiological findings between smear-positive non-tuberculous mycobacteria (NTM) and smear-negative, culture-positive NTM. Also, to evaluate the differences in clinical symptoms and radiological findings between Mycobacterium avium and M. intracellulare.

DESIGN

A retrospective study was performed of 200 cases with positive pulmonary cultures for NTM between January 1989 and December 1996. It was determined whether or not pulmonary disease was caused by NTM using the 1990 criteria recommended by the American Thoracic Society. Clinical symptoms and radiological findings were compared between groups.

RESULTS

Fever and hemoptysis were more frequently observed in smear-positive patients (26/50, 52%, and 24/50, 48%, respectively) than in smear-negative, culture-positive patients (8/38, 21.1%, P < 0.005, 8/38, 21.1%, P < 0.01, respectively). In addition, cavity formation was more frequently observed in chest computed tomography scans of smear-positive patients (19/36, 52.8%) than in smear-negative patients (6/31, 19.4%, P < 0.005). Finally, cavity formation tended to be more frequently observed with M. avium than with M. intracellulare.

CONCLUSION

The present study demonstrates differences in clinical symptoms and radiological findings between smear-positive and smear-negative NTM cases, as well as between M. avium and M. intracellulare.