Characterization of antimicrobial-resistant Escherichia coli causing urinary tract infections in dogs: Passive surveillance in Saskatchewan, Canada 2014 to 2018.

BACKGROUND

Urinary tract infections (UTIs) are common in dogs and can be caused by multidrug-resistant Escherichia coli (E coli).

OBJECTIVE

To describe the frequency and mechanisms of antimicrobial resistance (AMR) among E coli causing UTIs in dogs in Western Canada during a 4-year surveillance period.

ANIMALS: Urine from 516 dogs.

METHODS

From November 2014 to 2018, 516 nonduplicate E coli isolates from the urine of dogs were collected from a diagnostic laboratory. Susceptibility testing was determined for a panel of 14 antimicrobials belonging to 7 drug classes. Resistant isolates were screened for the presence of extended-spectrum beta-lactamases (ESBLs), AmpC β-lactamases, and plasmid-mediated quinolone resistance (PMQR) genes. Epidemiological relationships were assessed by MLST.

RESULTS

80.2% (414/516) of isolates were susceptible to all antimicrobials tested. There was no significant increase in the proportion of isolates resistant to any of the tested antimicrobials during the study period. Resistance to ampicillin was the most common (14.9%, 77/516). Overall, 12 isolates had blaCMY-2 -type AmpC β-lactamases, and 7 produced CTX-M-type ESBLs. A single isolate had the aac(6')-Ib-cr PMQR gene. The qnr and qepA determinants were not detected. A single isolate belonging to the pandemic lineage ST131 was identified.

CONCLUSION

Escherichia coli isolated from the urine of dogs in our region remain susceptible to first-line therapies, though resistance, particularly to the aminopenicillins, warrants monitoring. This is the first description of E coli ST131 from a companion animal in Canada.