Detection of Enterobacter cloacae complex strain with a bla_NDM-1-harboring plasmid from an elderly resident at a long-term care facility in Okayama, Japan

Amidst the global spread of antimicrobial resistance, New Delhi metallo-β-lactamase (NDM)-type carbapenemase-producing Enterobacterales (CPE) remain uncommon in Japan, and the detection of such highly drug-resistant organisms is limited to inbound cases. There is little evidence regarding the prevalence of NDM β-lactamase gene (bla_NDM)-harboring CPE in the domestic community, especially in the provincial cities of Japan. Herein, we report the isolation of a bla_NDM-1-harboring plasmid in Enterobacter cloacae complex strain isolated from an elderly woman without a history of traveling abroad who had resided in a long-term care facility in Okayama, Japan. The multidrug-resistant bla_NDM-harboring CPE isolate was detected in a stool sample of the patient during routine screening at admission. We performed whole-genome sequencing analysis of the isolate using MiSeq (Illumina) and MinION (Oxford Nanopore Technologies) platforms. The isolate was identified as sequence type 171, which has predominantly been reported in the United States and China. The bla_NDM-1 gene was encoded on the 46,161 bp IncX3 plasmid, with sequence similarity to plasmids of similar size isolated from individuals in China. Collectively, the genomic data suggest that an imported CPE isolate may have spread among healthy individuals in the regional area of Japan.