Epidemiological and Molecular Characteristics of Carbapenemase-Producing Enterobacteriaceae in a Tertiary Hospital in Korea: Possible Emergence of KPC-Producing Escherichia coli ST471 strain

BACKGROUND: Carbapenem-resistant Enterobacteriaceae (CRE) and especially carbapenemase-producing Enterobacteriaceae (CPE) were rare in Korea but have been rapidly increasing since 2015. CPE outbreaks are now common among Korean hospitals. We aimed to investigate the epidemiology and molecular characteristics of CPE clinical isolates at a tertiary hospital in the southeastern part of Korea. METHODS: CRE isolates, which had been isolated and stored from diagnostic or surveillance culture specimens between January 2011 and February 2017, were investigated. Multiple isolates from a patient were included in the study when they are of different species or separated by 30 days or more. Antibiogram was generated by the Vitek 2 system. Multiplex PCR was performed to detect 5 types of carbapenemases (KPC, NDM, VIM IMP, OXA). Of the PCR-positive CPE isolates, multi-locus sequence typing was performed for E. coli, K. pneumoniae and E. cloacae. For the patients with CPE, information on admission period, ward, room, bed position and common medical staff was collected to find epidemiologic link. RESULTS: Total 197 CRE isolates from 169 patients were investigated, and 65 isolates were CPE. The earliest CPE isolate was in January 2016. Of the CPE isolates, the most common species were E. coli (45%) and K. pneumoniae (43%); the most common carbapenemase types were KPC (80%) and NDM (14%). Two CPE strains with KPC, E. coli ST471 (18%) and K. pneumoniae ST307 (25%), were prevalent. KPC was mostly associated with K. pneumoniae (27/52) and E. coli (19/52), and NDM with E. coli (8/9) and K. pneumoniae (1/9). Between August 2016 and February 2017, there were 32 outbreak-associated CPE isolates from 9 clusters (5 E. coli clusters, 3 K. pneumoniae ones, 1 E. cloacae one). The largest cluster was of 7 patients from whom KPC-2-positive E. coliof ST471 lineage was isolated. CONCLUSION: Species of the CPE isolates in our hospital were mostly E. coli and K. pneumoniae, and KPC was the most common type of carbapenemase. KPC-positive E. coli ST471, not well-known in Korea and East-Asia, may be a newly emerging CPE strain. Although E. coli is known to only rarely cause CPE outbreaks, it might commonly cause in CPE outbreaks in the southeastern part of Korea. DISCLOSURES: All authors: No reported disclosures.