Abstract:
Successful treatment of canine pyoderma has become compromised owing to the development
of antimicrobial resistance with accompanying recurrence of infection. Canine skin samples
submitted to a veterinary diagnostic laboratory for microbiological culture and sensitivity
between January 2007 and June 2010, from which Staphylococcus intermedius was isolated, were
selected for this investigation. Antimicrobial resistance of S. intermedius was most prevalent
with reference to ampicillin followed by resistance to tetracycline and then potentiated
sulphonamides. In general, antimicrobial resistance was low and very few methicillinresistant
isolates were detected. Temporal trends were not noted, except for ampicillin, with
isolates becoming more susceptible, and potentiated sulphonamides (co-trimoxazole), with
isolates becoming more resistant. In general, both the Kirby–Bauer disc diffusion and broth
dilution minimum inhibitory concentration tests yielded similar results for the antimicrobial
agents tested. The main difference was evident in the over-estimation of resistance by the
Kirby–Bauer test for ampicillin, co-trimoxazole, penicillin and doxycycline. Knowledge
of trends in bacterial resistance is important for veterinarians when presented with canine
pyoderma. Analysis of antimicrobial susceptibility profiles of S. intermedius isolated from
canine pyodermas will guide veterinarians’ use of the most appropriate agent and encourage
prudent use of antimicrobials in companion animals.
