title: In vitro susceptibilities of Rickettsia and Bartonella spp. to 14-hydroxy-clarithromycin as determined by immunofluorescent antibody analysis of infected vero cell monolayers.
abstract: 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.
authors.affiliation: School of Pharmacy and Department of Family Medicine, School of Medicine, Campus Box 7595, University of North Carolina at Chapel Hill, NC 27599-7595, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Ives
authors.forename: E L
authors.initials: EL
authors.lastname: Marston
authors.forename: R L
authors.initials: RL
authors.lastname: Regnery
authors.forename: J D
authors.initials: JD
authors.lastname: Butts
authors.forename: T C
authors.initials: TC
authors.lastname: Majerus
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000494:pharmacology*; D001473:Bartonella / Q000187:drug effects*; D002522:Chlorocebus aethiops; D017291:Clarithromycin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D008826:Microbial Sensitivity Tests; D012281:Rickettsia / Q000187:drug effects*; D013752:Tetracycline / Q000494:pharmacology; D014709:Vero Cells
chemical_list: D000900:Anti-Bacterial Agents; C056228:14-hydroxyclarithromycin; D013752:Tetracycline; D017291:Clarithromycin