Frequency and antimicrobial susceptibility profiles of bacterial species isolated from canine and feline urine samples in Sydney, Australia, 2012–2021

Bacterial urinary tract infections are frequently diagnosed in veterinary practice and often treated empirically. Recommended treatment differs for sporadic versus recurrent infections. Antimicrobial selection is ideally informed by local antibiograms; however, this data is currently unavailable for dogs and cats in Sydney, Australia's largest city by population. The objectives of this retrospective study were to: i) identify the proportions of bacterial species in positive cultures from canine and feline urine samples submitted between 2012 and 2021 to a veterinary diagnostic laboratory in Sydney, Australia, ii) describe and compare antimicrobial susceptibility profiles between isolates from sporadic and recurrent positive cultures and iii) develop local antibiograms to facilitate evidence-based decisions around empiric therapy. A total of 1506 positive urine cultures were obtained from 567 dogs and 471 cats. The most frequently isolated bacteria were Escherichia coli (58 %), Enterococcus spp. (17 %), Staphylococcus spp. (13.4 %) and Proteus spp. (9 %). Eighty-three percent of bacterial isolates were susceptible to at least one first-line empirical choice (amoxicillin and/or trimethoprim-sulfonamide). E. coli had the highest percentage of multidrug-resistant isolates from animals with sporadic (32 %) and recurrent positive cultures (40 %). Susceptibility of E. coli to amoxicillin increased from 47 % in 2012 to 55 % in 2021. Susceptibility of S. pseudintermedius to amoxicillin-clavulanic acid and oxacillin decreased from 100 % in 2012 to 54 % in 2021.Twenty-two percent of S. pseudintermedius isolates were methicillin-resistant. Compared to reports from other locations, our findings suggest that amoxicillin may be less effective as a first-line choice for treating canine and feline UTI in Sydney.