Population Structure and Antimicrobial Resistance of Canine Uropathogenic Escherichia coli.

is the most common cause of human and canine urinary tract infection (UTI). Clonal groups, often with high levels of antimicrobial resistance, are a major component of the population that causes human UTI. While little is known about the population structure of that causes UTI in dogs, there is evidence that dogs and humans can share fecal strains of and that human-associated strains can cause disease in dogs. In order to better characterize the strains that cause canine UTI, we analyzed 295 isolates obtained from canine urine samples from five veterinary diagnostic laboratories and analyzed their multilocus sequence types, phenotypic and genotypic antimicrobial resistance profiles, and virulence-associated gene repertoires. Sequence type 372 (ST372), an infrequent human pathogen, was the predominant sequence type in dogs at all locations. Extended-spectrum β-lactamase-producing isolates with genes were uncommon in canine isolates but when present were often associated with sequence types that have been described in human infections. This provides support for occasional cross-host-species sharing of strains that cause extraintestinal disease and highlights the importance of understanding the role of companion animals in the overall transmission patterns of extraintestinal pathogenic .