Molecular Characteristics of NDM-5-Producing Escherichia coli from a Cat and a Dog in South Korea

Carbapenemase-producing Enterobacteriaceae (CPE) have been very rarely reported in companion animals in South Korea. In this study, we aimed to investigate the molecular characteristics and relatedness of two New Delhi metallo-beta-lactamase (NDM-5)-producing Escherichia coli isolates from rectal swabs of a dog and a cat hospitalized in different veterinary hospitals in South Korea during 2019. Antimicrobial susceptibility was tested by the Etest and broth microdilution method. PCR and sequencing were performed to detect antimicrobial resistance genes. Plasmid replicon typing and Southern blotting hybridization were performed to determine the replication origin of the plasmid and location of the bla(NDM-5) gene, respectively. Their macrorestriction profiles for E. coli isolates were assessed by multilocus sequence typing (MLST) and pulse-field gel electrophoresis (PFGE). The two carbapenem-resistant E. coli isolates harbored the bla(NDM-5) gene located on the IncX3 plasmid. Allele sequence analysis for MLST showed that the two E. coli isolates were attributed to sequence type 410 (ST410). The NDM-5-producing E. coli isolate from the cat presented high clonal similarity (94%) assessed by PFGE to a previously reported NDM-5-producing E. coli ST410 isolate from a dog hospitalized in the same hospital in 2017. The two E. coli isolates for the genetic environment surrounding the bla(NDM-5) gene had the same structure: ISAba125-bla(NDM-5)-ble(MBL)-trpF-TAT-ISCR26. This study revealed a direct transmission of the NDM-5-producing E. coli ST410 isolate between a dog and a cat. This is the first report of NDM-5 carbapenemase-producing E. coli isolate from a cat in South Korea.