Susceptibility of canine and feline Escherichia coli and canine Staphylococcus intermedius isolates to fluoroquinolones.
OBJECTIVE
1) A prospective study to determine in vitro concentrations for a range of fluoroquinolones, gentamicin and amoxycillin-clavulanate required to inhibit growth of recently collected, feline and canine Escherichia coli and canine Staphylococcus intermedius isolates. 2) A comparative retrospective study to compare the minimum inhibitory concentrations (MICs) of ciprofloxacin, enrofloxacin and amoxycillin-clavulanate for archived canine E coli and S intermedius isolates collected ten to twenty years earlier, with those for recently collected isolates.


METHODS
Susceptibility was assessed using disk diffusion, agar dilution susceptibility testing and Epsilometer tests (E-tests) for both recently collected and archived isolates.


RESULTS
All feline E coli isolates and recently collected canine S intermedius isolates were susceptible to all fluoroquinolones. There was a statistically significant increase in the MIC range of ciprofloxacin and enrofloxacin for recently collected E coli, and in the MIC range of amoxycillin-clavulanate for recently collected S intermedius isolates compared to archived isolates. Twelve of 59 recently collected canine E coli isolates were resistant to both ciprofloxacin and enrofloxacin. Resistant canine E coli isolates were associated with complicating host or infection site factors.


CONCLUSIONS
This is the first report comparing the MICs for all veterinary fluoroquinolones currently available in Australia for a representative sample of canine and feline E coli and canine S intermedius isolates. Importantly, this study identified 12 of 59 canine E coli isolates resistant to fluoroquinolones and identified the development of low level resistance in canine E coli to ciprofloxacin and enrofloxacin and canine S intermedius to amoxycillin-clavulanate.
Gottlieb
S
S
Faculty of Veterinary Science, The University of Sydney, NSW 2006.
Wigney
D I
DI
Martin
P A
PA
Norris
J M
JM
Malik
R
R
Govendir
M
M
D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002371:Cat Diseases / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D002415:Cats; D004283:Dog Diseases / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D004285:Dogs; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000662:veterinary; D024841:Fluoroquinolones / Q000494:pharmacology* / Q000627:therapeutic use; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D009517:New South Wales / Q000453:epidemiology; D011446:Prospective Studies; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000662:veterinary; D013210:Staphylococcus / Q000187:drug effects* / Q000302:isolation & purification
D000890:Anti-Infective Agents; D024841:Fluoroquinolones