The gene for New Delhi metallo-β-lactamase-5 (NDM-5) in Escherichia coli has been identified in many countries mainly from human clinical specimens. The isolates carrying this gene are even more rarely isolated from companion animals. In this study, four carbapenem-resistant isolates were recovered from four dogs in Korea. All isolates carried blaNDM-5 and exhibited resistance to meropenem and imipenem, and were susceptible to colistin. Epidemiological analysis showed that all four isolates were sequence type 410 (ST410) and shared 99% similarity as determined by pulsed-field gel electrophoresis analysis. Among the four isolates, the Z0117EC0033 strain was randomly selected for whole-genome sequencing, composed of a 4.7Mb circularized chromosome carrying the CMY-2 gene and two plasmids. The first plasmid of the IncFIB type had 83 coding sequences (CDS) in ca. 74 kb. The second smaller plasmid of the IncX3 type had 57 CDS and carried only the blaNDM-5 gene in ca. 46 kb. The plasmid structures were highly similar (> 99%) to those of the NDM-5 human-like IncX3 plasmid. This is the first report of carbapenemase-producing Enterobacteriaceae from companion animals in Korea. The human-like blaNDM-5 IncX3 plasmid identified in this study suggests a potential transmission route of the NDM-5 plasmid between humans and companion animals.
Keywords: IncX3 plasmid; NDM-5; companion animal.