Occurrence of antimicrobial resistant bacteria in healthy dogs and cats presented to private veterinary hospitals in southern Ontario: A preliminary study

Abstract

The prevalence and patterns of antimicrobial susceptibility of fecal Escherichia coli, Salmonella spp., extended beta-lactamase producing E. coli (ESBL-E. coli), methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-resistant Staphylococcus pseudintermedius (MRSP) were determined for healthy dogs (n = 188) and cats (n = 39) from veterinary hospitals in southern Ontario that had not had recent exposure to antimicrobials. The prevalence of antimicrobial resistance in E. coli was as follows: streptomycin (dogs - 17%, cats - 2%), ampicillin (dogs - 13%, cats - 4%), cephalothin (dogs - 13%, cats - < 1%), and tetracycline (dogs - 11%, cats - 2%). Eleven percent of dogs and 15% of cats had isolates that were resistant to at least 2 antimicrobials. Cephamycinase (CMY)-2 producing E. coli was cultured from 2 dogs. No Salmonella spp., ESBL-E. coli, MRSA, or MRSP isolates were recovered. The observed prevalence of resistance in commensal E. coli from this population was lower than that previously reported in companion animals, but a small percentage of dogs may be a reservoir for CMY-2 E. coli.

Figure 1

Number of phenotypically distinct antimicrobial susceptibility patterns among 5 commensal Escherichia coli isolates recovered from individual dog and cat fecal samples when the Kirby-Bauer disc diffusion method was used.

Figure 2

Percentage of dogs (n = 113) and cats (n = 39) with Escherichia coli isolates that were resistant to 2–8 antimicrobials when broth microdilution^a was used. ^a Susceptibility testing, using broth microdilution, was performed on presumptive ESBL E. coli isolates and commensal E. coli isolates that were classified as intermediate or resistant, using the Kirby-Bauer disc diffusion method.