Emergence of Enterobacter cloacae Complex Co-Producing IMP-10 and CTX-M, and Klebsiella pneumoniae Producing VIM-1 in Clinical Isolates in Japan

Carbapenemase-producing Enterobacteriaceae (CPE) are an emerging threat in healthcare settings worldwide. We evaluated the presence of carbapenemase genes in CPE in a tertiary care university hospital in Tokyo, Japan. Carbapenem-resistant clinical isolates were collected in 2018 at Teikyo University Hospital (Tokyo, Japan). Bacterial species were identified using MALDI-TOF MS. Carbapenemase production was evaluated using a carbapenemase inactivation method. The presence of carbapenemase genes was confirmed by multiplex PCR and DNA sequencing. Four CPE isolates were identified: two complex strains and and strains. Three of the isolates ( complex and ) were IMP-1-type producers, including IMP-10 in their produced metallo-β-lactamase, and are epidemic in East Japan. The IMP-10-producing complex strain also produced CTX-M ESBL. The other CPE isolate ( ) is a VIM-1 producer. VIM-1-producing is epidemic in Europe, especially in Greece. Accordingly, the VIM-1 producer was isolated from a patient with a medical history in Greece. This study revealed the emergence of complex co-producing IMP-1-type carbapenemase and CTX-M ESBL, and producing VIM-1 carbapenemase in clinical isolates in Japan. Metallo-β-lactamase was the most prevalent type of carbapenemase at Teikyo University Hospital, especially IMP-1-type carbapenemase. The detection of VIM-1-producing suggests that epidemic CPE from overseas can spread to countries with low CPE prevalence, such as Japan, highlighting the need for active surveillance.