In vitro susceptibilities of Rickettsia and Bartonella spp. to 14-hydroxy-clarithromycin as determined by immunofluorescent antibody analysis of infected vero cell monolayers

J Antimicrob Chemother. 2000 Mar;45(3):305-10. doi: 10.1093/jac/45.3.305.


The in vitro susceptibilities of Rickettsia akari, Rickettsia conorii, Rickettsia prowazekii, Rickettsia rickettsii, Bartonella elizabethae, Bartonella henselae and Bartonella quintana to different concentrations of clarithromycin, 14-hydroxy-clarithromycin (the primary metabolite of clarithromycin) and tetracycline in Vero cell cultures, were determined by enumeration of immunofluorescently-stained bacilli. The extent of antibiotic-induced inhibition of foci was recorded for each dilution of antibiotic and compared with an antibiotic-negative control. Based upon MIC data, clarithromycin alone is highly active against all three Bartonella spp., R. akari and R. prowazekii, while 14-hydroxy-clarithromycin is active against R. conorii, R. prowazekii and R. rickettsii. Further testing is warranted in animal models and human clinical trials, to examine the activity of both clarithromycin and its primary metabolite and to define further the role of clarithromycin in therapy, particularly of infections caused by obligate intracellular bacteria such as Rickettsia and Bartonella spp.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / pharmacology*
  • Bartonella / drug effects*
  • Chlorocebus aethiops
  • Clarithromycin / analogs & derivatives*
  • Clarithromycin / chemical synthesis
  • Clarithromycin / pharmacology
  • Fluorescent Antibody Technique
  • Microbial Sensitivity Tests
  • Rickettsia / drug effects*
  • Tetracycline / pharmacology
  • Vero Cells


  • Anti-Bacterial Agents
  • 14-hydroxyclarithromycin
  • Tetracycline
  • Clarithromycin