Frequency and Antimicrobial Susceptibility Patterns of Canine and Feline Urinary Tract Pathogens: A 6-Year (2018–2023) Retrospective Study in Phoenix, Arizona, United States

This retrospective study is intended to contribute to the ongoing investigations of antimicrobial resistance in companion animals by specifically examining the demographics, sex, rates of resistance, and multidrug resistance of bacteria isolated from urine samples of cats and dogs suspected of urinary tract infections (UTIs) in Arizona, USA, between 2018 and 2023. Escherichia coli was the most isolated bacterium with an overall frequency of 43.4%, followed by Enterococcus faecalis (11.5%), Proteus mirabilis (10.7%), Staphylococcus pseudintermedius (9.9%), Enterococcus faecium (6.9%), and Klebsiella pneumoniae (6.3%). Each year, culture-positive canine urine samples were more frequent than positive feline samples, with summer months producing the majority of suspected UTI samples for dogs and cats. Age played a role for culture-positive urine samples only in female dogs, with no association between age or sex and the number of positive feline samples. Feline Escherichia coli and Klebsiella pneumoniae isolates demonstrated more resistance to penicillins + beta-lactamase inhibitors than canines. The feline Enterococcus faecalis isolates also revealed significantly more resistance than canine isolates to penicillins + beta-lactamase inhibitors. In terms of multidrug resistance, a significant difference was found between the isolates of both Klebsiella pneumoniae and Proteus mirabilis and other bacterial species. These findings contribute to the relevant role antimicrobial surveillance plays in the prevention and control of UTI pathogens in companion animals. Because dogs and cats often are in close contact with their owners, they may be potential sources for human infection and a One Health concern.