Short-course chemotherapy for pulmonary disease caused by Mycobacterium kansasii.

Forty patients with pulmonary disease caused by Mycobacterium kansasii were treated initially with rifampin, isoniazid, and ethambutol daily for 12 months, and with streptomycin twice weekly for the first 3 months. Postchemotherapy follow-up examinations have ranged from 6 to 68 months, with an average of 31 months. One of the 40 patients (2.5%) relapsed 6 months after completion of chemotherapy. In vitro susceptibility of the mycobacteria to the drugs used, extent of disease, and/or the coexistence of other diseases did not seem to influence the outcome. This 12-month chemotherapy regimen is considered to be sufficient for the initial treatment of pulmonary disease caused by M. kansasii.