Disseminated Mycobacterium avium complex (MAC)
infection continues to be a common
opportunistic infection in patients infected with human immunodeficiency virus (HIV). The optimal
therapy for disseminated MAC
infection is unclear. We compared
azithromycin plus
ethambutol with
clarithromycin plus
ethambutol in the treatment of disseminated MAC
infection in HIV type 1-infected patients, examining the frequency of
bacteremia clearance, time to clearance, and study drug tolerance after 16 weeks of
therapy. Fifty-nine patients for whom blood cultures were positive for MAC were enrolled in the study from 10 university-affiliated Veterans Affairs Medical Centers. Thirty-seven patients were evaluable for determination of quantitative
bacteremia and clinical outcomes. Clearance of
bacteremia was seen at the final visit in 37.5% of
azithromycin-treated patients and in 85.7% of
clarithromycin-treated patients (P = .007). The estimated median time to clearance of
bacteremia was also significantly different between the two treatment arms: 4.38 weeks for
clarithromycin recipients vs. > 16 weeks for
azithromycin recipients (P = .0018). Only one isolate developed
macrolide resistance during
therapy. Abatement of symptoms, other laboratory-evident abnormalities, and adverse effects were similar in the two groups. At the doses used in this study,
clarithromycin/
ethambutol produced a more rapid resolution of
bacteremia than did
azithromycin/
ethambutol, and
clarithromycin/
ethambutol was more effective at sterilization of blood cultures after 16 weeks of
therapy.