Characterization of Phylogroups, Virulence Factors and Antimicrobial Resistance in Canine Pyometra-associated...

The presence of multidrug-resistant extraintestinal pathogenic Escherichia coli (ExPEC) in pets poses a significant threat to animal health and represents a potential source of antimicrobial resistance with zoonotic transmission to humans. A total of 56 pyometra swab samples from dogs were analysed for the presence of E. coli using standard microbiological procedures. Phylogrouping of the E. coli isolates was performed using the quadruplex, and 12 virulence genes were detected by single polymerase chain reaction (PCR) method. Antimicrobial susceptibility testing was conducted against 12 antimicrobial agents in five different classes using the Kirby-Bauer disc diffusion method. E. coli was isolated from all 56 swab samples of pyometra cases using 5% ovine blood agar and MacConkey agar, and identified with Eosin Methylene Blue agar, Methyl Red and Voges-Proskauer tests. fimH was found in all strains. The most common virulence genes were fyuA (96.4%), usp (83.9%), sfa (73.2%), hlyA (69.6%), cnf1 (69.6%), papGIII (64.2%), and papC (58.9%). The least common virulence gene was iucD,while none of the strains carried afa and papG allelic variants (papGI and II). A total of 83.9% of isolates belonged to phylogenetic group B2. All isolates were resistant to amoxicillin/clavulanic acid, ampicillin and lincomycin but sensitive to amikacin. The multidrug resistance (MDR) rate was 58.9% (33/56 isolates). MDR and multiple antibiotic resistance index (MARI) scores were similar between the groups (p > 0.05). The phylogenetic analysis revealed that resistant isolates were found across all detected phylogroups, with strains from different phylogroups sharing the same virulence genes. E. coli from pyometra cases in companion animals is largely associated with resistance and possesses virulence genes enabling efficient colonization and carriage.