[Therapeutic efficacy of macrolide in pulmonary nontuberculous mycobacteriosis].

Clarithromycin (CAM) is semi-synthetic macrolide antimicrobial agent, differing from erythromycin by an O-methyl substitution at position 6 of the 14-membered lactate ring. CAM is one of the very few antimicrobial agents that show activity against that Mycobacterium avium complex (MAC) in vivo, in vitro, and in AIDS patients with disseminated infections. The purpose of the present study was to evaluate the therapeutic efficacy of CAM against MAC in patients with chronic pulmonary MAC infection. In vitro activity against clinically isolated MAC; MIC was evaluated by liquid medium dilution method. CAM was the most effective than other antitubercular drugs against M. avium, but less effective than RFP against M. intracellulare. Activity in animal model of infection; In vivo activity was evaluated by the murine models of hematogenous pulmonary MAC infection. A dose-related reduction in lung cell counts was noted with treatment at 10, 50, 150, and 300 mg/kg of body weight administrated daily. Histopathological examinations were revealed also the reduction of the numbers of granulomas in the lungs with treatment CAM at 300 mg/kg. Therapeutic efficacy of CAM in chronic pulmonary MAC infection; Thirty patients with chronic pulmonary MAC infection were given CAM with other antitubercular drugs. Nineteen of 30 patients had previously received combination antimycobacterial therapy. The overall efficacy rates were 23.3%, and ten patients (33.3%) had negative sputum culture for MAC. Eradication of MAC from sputum has been almost observed within 3 months of initiating treatment, and the patients those who had no cavitation were effective. In conclusion, CAM was considerably effective against chronic pulmonary MAC infection, and the effect was observed relatively rapid.