title: Efficacy of azithromycin and rifabutin in preventing infection by Mycobacterium avium complex in beige mice.
abstract: We investigated the potential of the azalide, azithromycin, and rifabutin in preventing disseminated infection due to Mycobacterium avium complex (MAC) in beige mice. Azithromycin 200 mg/kg, rifabutin (30 mg/kg or 60 mg/kg) were administered by gavage 6 days before mice were challenged orally with 10(8) cfu MAC and daily for 10 days thereafter during which time the mice were again challenged with the same inoculum on alternate days (days +1, +3, +5, +7, and +9). Sixty-four days later, the presence of bacteria in the blood and the number of viable bacteria in liver, spleen and appendix were estimated. Treatment with azithromycin and 60 mg/kg/day rifabutin but not 30 mg/kg/day, significantly decreased the incidence of bacteraemia and the number of bacteria in the appendix. The administration of azithromycin resulted in significantly fewer MAC in the liver and spleen but not in the appendix whereas the converse was true of 60 mg/kg rifabutin. Our results indicate that both azithromycin and rifabutin can prevent MAC disseminated infection, but that the azalide is more effective than the rifamycin in reducing the burden of infection.
authors.affiliation: Kuzell Institute for Arthritis and Infectious Diseases, California Pacific Medical Center Research Institute, San Francisco 94115, USA.
authors.forename: L E
authors.initials: LE
authors.lastname: Bermudez
authors.forename: M
authors.initials: M
authors.lastname: Petrofsky
authors.forename: C B
authors.initials: CB
authors.lastname: Inderlied
authors.forename: L S
authors.initials: LS
authors.lastname: Young
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001065:Appendix / Q000382:microbiology; D017963:Azithromycin / Q000008:administration & dosage / Q000627:therapeutic use*; D016470:Bacteremia / Q000517:prevention & control; D005260:Female; D008099:Liver / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D015269:Mycobacterium avium Complex / Q000187:drug effects*; D015270:Mycobacterium avium-intracellulare Infection / Q000382:microbiology / Q000517:prevention & control*; D017828:Rifabutin / Q000627:therapeutic use*; D013154:Spleen / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D017828:Rifabutin; D017963:Azithromycin