title: Comparative activity of azithromycin and doxycycline against Brucella spp. infection in mice.
abstract: The activities of a short therapeutic regimen with azithromycin and the classic treatment doxycycline with streptomycin were compared and evaluated in mice infected with Brucella melitensis. In a chronic model, starting therapy 31 days after challenge, azithromycin (10 days, 50 mg/kg/day) significantly reduced the infection (2.9 logs, day 48 post-infection). The effectiveness of doxycycline (21 days, 50 mg/kg/12 hourly) was greater than azithromycin (4.1 logs of reduction, day 48 post-infection), and when doxycycline was administered for a period of 45 days, all the animals were bacteriologically cured from day 78. The combination with streptomycin (14 days, 10 mg/kg/day) did not improve the effect of any of the regimens. In an acute model infection, treatments with doxycycline or doxycycline-streptomycin, for a period of 3 days, starting 1 day after lethal challenge, were able to protect all the mice. In contrast, only 50% of the mice treated with azithromycin survived the challenge. In conclusion, although a short oral treatment with azithromycin was able to reduce the infection significantly, it was not able to cure the animals as effectively as the classic regimen with doxycycline administered for a longer period of time.
authors.affiliation: Dpto. de Microbiología, Clínica Universitaria de Navarra, Pamplona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Domingo
authors.forename: I
authors.initials: I
authors.lastname: Gastearena
authors.forename: A I
authors.initials: AI
authors.lastname: Vitas
authors.forename: I
authors.initials: I
authors.lastname: López-Goñi
authors.forename: C
authors.initials: C
authors.lastname: Dios-Viéitez
authors.forename: R
authors.initials: R
authors.lastname: Díaz
authors.forename: C
authors.initials: C
authors.lastname: Gamazo
mesh_terms: D000208:Acute Disease; D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D017963:Azithromycin / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D002003:Brucella abortus / Q000187:drug effects; D017347:Brucella melitensis / Q000187:drug effects*; D002006:Brucellosis / Q000188:drug therapy* / Q000382:microbiology; D002908:Chronic Disease; D004318:Doxycycline / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D004359:Drug Therapy, Combination / Q000627:therapeutic use; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D009929:Organ Size; D013154:Spleen / Q000382:microbiology; D013307:Streptomycin / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin; D004318:Doxycycline; D013307:Streptomycin