Molecular Epidemiology of Carbapenem-Resistant in Japan.

Information regarding haboring carbapenemase in Japan is limited. A comprehensive nationwide survey was conducted from September 2014 to December 2022, and 67 non-duplicate strains of carbapenem-resistant were isolated from 57 healthcare facilities in Japan. Through genetic testing and whole-genome sequencing, six strains were found to possess carbapenemases, including imipenemase (IMP)-1, IMP-6, New Delhi metallo-β-lactamase (NDM)-1, and NDM-5. The strain harboring was the novel strain ST709, which belongs to the clonal complex of the predominant ST4 in China. The novel integron containing featured the oxacillinase-101 gene, which is a previously unreported structure, with an IncN plasmid type. However, integrons found in the strains possessing , which were the most commonly identified, matched those reported domestically in , suggesting the prevalence of identical integrons. Transposons containing are similar or identical to the transposon structure of harboring previously reported in Japan, suggesting that the same type of transposon could have been transmitted to in Japan. This investigation analyzed mobile genetic elements, such as integrons and transposons, to understand the spread of carbapenemases, highlighting the growing challenge of carbapenem-resistant in Japan and underscoring the critical need for ongoing surveillance to control these pathogens.