Prevalence and Characterization of Extended-Spectrum β-Lactamase-Producing Isolated from Dogs and Cats in South Korea

Overall, 836 isolates (695 isolates from dogs and 141 from cats) were recovered from the diarrhea, skin/ear, urine, and genitals of dogs and cats between 2018 and 2019. Cefovecin and enrofloxacin resistance were noted in 17.1% and 21.2% of isolates, respectively. The cefovecin and enrofloxacin resistance rates were higher in dog isolates (18.1% and 22.9%) compared with the rates in cat isolates (12.1%, 12.8%). Interestingly, resistance to both antimicrobials was noted in 10.8% (90/836) of the isolates, predominantly in isolates from dogs. , , and were the most frequent extended-spectrum β-lactamase/plasmid-mediated AmpC β-lactamase (ESBL/AmpC)- gene types. The co-existence of was noted in six isolates from dogs. Sequencing analysis demonstrated that S83L and D87N in and S80I in were the most frequent point mutations in the quinolone resistance-determining regions of the cefovecin and enrofloxacin-resistant isolates. A total of 11 isolates from dogs carried the plasmid-mediated quinolone resistance genes (six , four , and one ), while only two cat isolates carried the gene. Multilocus sequence typing of the cefovecin and enrofloxacin-resistant isolates revealed that sequence type (ST)131 carrying and genes and ST405 carrying gene were predominant among the isolated strains. The majority of the ESBL/AmpC-producing isolates displayed diverse pulsed-field gel electrophoresis profiles. This study demonstrated that third-generation cephalosporin- and fluoroquinolone-resistant were widely distributed in companion animals. The detection of the pandemic ST131 clone carrying - in companion animals presented a public health threat.