title: In-vitro and in-vivo susceptibility of Borrelia burgdorferi to azithromycin.
abstract: The in-vitro and in-vivo susceptibility of Borrelia burgdorferito tetracycline, erythromycin and azithromycin was investigated. A macrodilution broth technique was used to determine MBCs. B. burgdorferi was most susceptible to azithromycin (MBC 0.04 mg/l) followed by erythromycin (MBC 0.16 mg/l) and tetracycline (MBC 1.6 mg/l). Syrian hamsters were used to determine ED50S for the three antimicrobials. Azithromycin was most effective in the elimination of spirochaetes from experimentally infected hamsters with an ED50 of 3.71 (+/- 1.9) mg/kg followed by tetracycline (ED50 15.6 (+/- 4.58) mg/kg). Erythromycin possessed low activity, having an ED50 of 122.2 (+/- 51.9) mg/kg. Tissue concentrations of azithromycin exceeding the MBC were present 24 h after the final treatment.
authors.affiliation: Department of Microbiology, University of Minnesota, Minneapolis 55455.
authors.forename: R C
authors.initials: RC
authors.lastname: Johnson
authors.forename: C
authors.initials: C
authors.lastname: Kodner
authors.forename: M
authors.initials: M
authors.lastname: Russell
authors.forename: D
authors.initials: D
authors.lastname: Girard
mesh_terms: D000818:Animals; D017963:Azithromycin; D015748:Borrelia burgdorferi Group / Q000187:drug effects*; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000032:analysis / Q000494:pharmacology; D008193:Lyme Disease / Q000188:drug therapy / Q000378:metabolism; D008647:Mesocricetus; D013752:Tetracycline / Q000494:pharmacology; D014018:Tissue Distribution
chemical_list: D004917:Erythromycin; D017963:Azithromycin; D013752:Tetracycline