Abstract
The rapid spread of Carbapenem-resistant Enterobacteriaceae (CRE) has led to a worldwide public health crisis. The rapid rise in CRE infections during coronavirus disease 2019 pandemic has emphasized the need to analyze the characteristics, resistance mechanisms, and genetic relatedness of CRE isolated in the Republic of Korea (ROK). A total of 15,639 CRE isolates were identified by laboratory testing in 2021, with two species: Klebsiella pneumoniae (10,643 strains, 68.1%) and Escherichia coli (2,718 strains, 17.4%) accounting for 85.5% of total isolates. The number of CRE isolates by region has increased every year and the isolation rate in the metropolitan area (8,229 strains, 52.6%) was higher than that of any other region. In addition, 99.1% of isolates were resistant to one or more carbapenem agent such as ertapenem. Carbapenemase-producing Enterobacteriaceae (CPE) was accounted for 83.0% (12,979 strains) of the total CRE isolates, and the major carbapenemase subtype in the ROK was KPC-2 (10,314 strains, 79.4%). The genetic relationship among carbapenem-resistant-K. pneumoniae (CR-K. pneumoniae) isolates showed that three genotypes had spread nationwide. Furthermore, other genotypes of CR-K. pneumoniae were prevalent in 6 regions, suggesting that regional spreads may have been caused by the same or a specific clone. This study evaluated the prevalence of CRE in the ROK and focused on the characteristics and genetic relationship of CRE. It is expected to be used as basic data when responding to future national infectious disease crises caused by antibiotic-resistant bacteria.