Molecular characterization of uropathogenic Escherichia coli (UPEC) strains isolated from companion dogs and cats in Korea.

Importance: Urinary tract infections (UTIs) are common and significant health issues in pets. Although extensive international research exists on their prevention and treatment, a notable gap remains in analyzing the characteristics of the causative bacteria.

Objective: To investigate the phylogroup, antimicrobial resistance (AMR), and molecular genotype of Escherichia coli isolates from dogs and cats with UTIs in animal clinics in Korea.

Methods: Uropathogenic E. coli (UPEC) strains were analyzed for phylogenetic grouping polymerase chain reaction, AMR, transferable resistance plasmids, and multilocus sequence typing.

Results: Sixty-seven UPECs were isolated from urine samples of dogs (n = 57) and cats (n = 10). Regarding age, the incidence of UTI was the highest in the 11 to 15 years range (46.3%, 31/67). Regarding sex, it accounted for 58.2% (n = 39) in female dogs and 11.9% (8/67) in female cats. Phylogroup B2 was the most frequent (n = 51, 75.0%) among all strains, followed by D (16.2%), A (7.4%), and B1 (1.5%). Thirty-seven (55.2%) UPECs were multidrug-resistant (MDR), and 24 (35.8%) of them belonged to phylogroup B2. Extended-spectrum cephalosporin and carbapenemase genes were detected in 18 (26.9%) UPECs and plasmids carrying these resistance genes were conjugated between strains. Thirty sequence types (STs) were identified among the total strains. Among the UPECs (n = 51) with phylogroup B2, 23 STs were identified, with ST73 being the most frequent (n = 12, 17.9%), followed by ST131 (n = 9, 13.4%).

Conclusions and relevance: Phylogroup B2 strains, particularly ST73 and ST121, were most prevalent in UPECs from Korean companion dogs and cats. For MDR UPECs, appropriate antibiotic selection is essential for the treatment of UTIs.