Comparative activity of azithromycin and doxycycline against Brucella spp. infection in mice

J Antimicrob Chemother. 1995 Oct;36(4):647-56. doi: 10.1093/jac/36.4.647.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Animals
  • Anti-Bacterial Agents / pharmacokinetics
  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use*
  • Azithromycin / pharmacokinetics
  • Azithromycin / pharmacology
  • Azithromycin / therapeutic use*
  • Brucella abortus / drug effects
  • Brucella melitensis / drug effects*
  • Brucellosis / drug therapy*
  • Brucellosis / microbiology
  • Chronic Disease
  • Doxycycline / pharmacokinetics
  • Doxycycline / pharmacology
  • Doxycycline / therapeutic use*
  • Drug Therapy, Combination / therapeutic use
  • Female
  • Mice
  • Mice, Inbred BALB C
  • Organ Size
  • Spleen / microbiology
  • Streptomycin / pharmacology
  • Streptomycin / therapeutic use


  • Anti-Bacterial Agents
  • Azithromycin
  • Doxycycline
  • Streptomycin