New macrolide antibiotics: usefulness in infections caused by mycobacteria other than Mycobacterium tuberculosis

OBJECTIVE: To compare the pharmacology, in vitro activity, and clinical use of the new macrolide antibiotics, azithromycin and clarithromycin, in the treatment of infections caused by mycobacteria other than Mycobacterium tuberculosis. DATA IDENTIFICATION: An English-language literature search using MEDLINE (1987-1994), Index Medicus (1987-1994), Program and abstracts of the 31st (1991) and 32nd (1992) Interscience Conference on Antimicrobial Agents and Chemotherapy, and bibliographic reviews of related textbooks, review articles, and professional society publications. STUDY SELECTION: 105 articles were selected. In vitro and in vivo reports on the pharmacokinetics, microbiology, pharmacology, and effectiveness of clarithromycin and azithromycin were assessed to compare their effectiveness and safety. Emphasis was placed on the use of these new drugs in treating infections caused by Mycobacterium avium complex, Mycobacterium chelonae, and Mycobacterium fortuitum infections. RESULTS: A review of the in vitro activity of the new macrolides revealed moderate to very good activity against many strains of mycobacteria other than M. tuberculosis. Early clinical trials show promising results in pulmonary infections, lymphadenitis, cutaneous infections, and disseminated infections. CONCLUSIONS: The new macrolides, azithromycin and clarithromycin, show great promise for treating infections caused by these acid-fast bacteria. Clarithromycin is recommended as a component of combination therapy for the treatment of M. avium complex infections in patients with AIDS. The development of resistance in patients, particularly when these agents are used alone, has been reported.