title: In vitro activity of chloramphenicol, florfenicol and enrofloxacin against Chlamydia pecorum isolated from koalas (Phascolarctos cinereus).
abstract: OBJECTIVE
  To determine the in vitro susceptibilities of koala isolates of Chlamydia pecorum to enrofloxacin and chloramphenicol, which are frequently used to treat koalas with chlamydiosis, and florfenicol, a derivative of chloramphenicol.
  
  
  METHODS
  The in vitro susceptibilities were determined by culturing three stored isolates and seven clinical swabs of C. pecorum. Susceptibility testing was undertaken using cycloheximide-treated buffalo green monkey kidney cells in 96 well microtitre plates.
  
  
  RESULTS
  The minimum inhibitory concentrations (MICs) for all isolates were 0.25-0.50 µg/mL (enrofloxacin), 1-2 µg/mL (chloramphenicol), and 1-2 µg/mL (florfenicol). Minimum bactericidal concentration (MBC) values for five isolates were also determined and were within one two-fold dilution of MICs. The MICs and MBCs of these antimicrobials were within ranges previously reported for other chlamydial species.
  
  
  CONCLUSIONS
  When combined with previously published pharmacokinetic data, the in vitro susceptibility results support chloramphenicol as a more appropriate treatment option than enrofloxacin for koalas with chlamydiosis. The susceptibility results also indicate florfenicol may be an appropriate treatment option for koalas with chlamydiosis, warranting further investigation.
authors.affiliation: McMaster Building B14, Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia.
authors.forename: L A
authors.initials: LA
authors.lastname: Black
authors.affiliation: McMaster Building B14, Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia.
authors.forename: D P
authors.initials: DP
authors.lastname: Higgins
authors.affiliation: McMaster Building B14, Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia. merran.govendir@sydney.edu.au.
authors.forename: M
authors.initials: M
authors.lastname: Govendir
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002689:Chlamydia / Q000187:drug effects*; D002690:Chlamydia Infections / Q000188:drug therapy / Q000662:veterinary; D002701:Chloramphenicol / Q000494:pharmacology*; D002522:Chlorocebus aethiops; D000077422:Enrofloxacin; D024841:Fluoroquinolones / Q000494:pharmacology*; D066298:In Vitro Techniques; D008826:Microbial Sensitivity Tests; D048368:Phascolarctidae; D013839:Thiamphenicol / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D024841:Fluoroquinolones; D000077422:Enrofloxacin; D002701:Chloramphenicol; C035534:florfenicol; D013839:Thiamphenicol
keywords: Chlamydia pecorum; antimicrobial susceptibility; chloramphenicol; enrofloxacin; florfenicol; koalas