[A study on the effect of combined chemotherapy on Mycobacterium avium complex pulmonary disease]

Annual incidence of Mycobacterium avium complex (MAC) pulmonary disease has been gradually increasing in the last 10 years in Japan, however, the optimal therapeutic regimen for the disease has not yet established. We investigated the effect of our new regimen in twenty seven cases of pulmonary MAC infection without HIV infection, diagnosed according to the American Thoracic Society criteria during the period from January 1996 to October 1997 at our hospital. These patients were treated with rifampicin (RFP), ethambutol (EB) and clarithromycin (CAM) for more than 12 months, together with streptomycin (SM) initially (first 2-3 months), except one patient who was treated for 11 months only. Twenty-four months after the therapy, sputum cultures converted from positive to negative in 13 patients and the amount of bacilli in sputum reduced in two patients. The radiological findings improved in 10 patients, showed no significant changes in 11 patients, while worsened in the remaining 6 patients. As to adverse reactions 1 case of liver damage, 3 cases of skin disorders, 4 cases of gastrointestinal malfunctions, and 1 case of optic neuritis were observed. This regimen was safe and tolerable even in the elderly outpatients, but not so effective against MAC pulmonary disease compared with the results of recent reports from the U.S. and Europe. Size of pulmonary lesions was closely associated with the effectiveness in this study. However, five bacteriologically converted cases did not show radiological improvement, and the reasons behind this fact remain to be investigated.