Occurrence of antimicrobial resistance in selected bacteria in healthy dogs and cats presented to private veterinary clinics in southern Ontario (Escherichia coli, Salmonella, Staphylococcus aureus, Staphylococcus intermedius)

This thesis is an investigation of the prevalence and risk factors associated with antimicrobial resistance in Escherichia coli, extended spectrum beta-lactamase (ESBL) E. coli, Salmonella and methicillin-resistant Staphylococcus aureus (MRSA) and Staph. intermedius (MRSI) in companion animals. Healthy dogs and cats without recent exposure to antimicrobials were enrolled from private veterinary clinics. Five isolates of E. coli were recovered from each animal, but no isolates of Salmonella, MRSA/MRSI or ESBL-E. coli were recovered. A low prevalence of resistance was observed to the antimicrobials tested, yet multiple drug-resistance was observed. Three isolates of CMY-2 E. coli were recovered. Carriage of antimicrobial resistant/intermediately susceptible E. coli was associated with consumption of raw meat, raw bones and pig ear treats, and antimicrobial therapy, in particular with short acting penicillin and enrofloxacin. This study is the first systematic investigation of the occurrence of antimicrobial resistance in commensal E. coli isolated from dogs and cats.