Dissemination of the high-risk clone ST147 carbapenem-resistant Klebsiella pneumoniae from a local tertiary care hospital in the Republic of Korea

Abstract

Background : The emergence of carbapenem-resistant Enterobacterales (CRE) infections is rapidly increasing and represents a serious public threat. In 2020, a total of 16,883 carbapenemase-producing Enterobacterales strains were collected; among these isolates, 21 strains were repeatedly isolated in a local tertiary care hospital. Methods : Antimicrobial susceptibility testing was performed using the broth microdilution method. All 21 strains of CRKP were analyzed by PFGE after XbaI digestion. The 21 CRKP strains were sequenced on the Illumina Miseq and Oxford Nanopore GridION platforms. Results : These 21 CRKP isolates showed an identical antimicrobial resistance profile, such as resistance to ampicillin, carbapenems, cephems, chloramphenicol, fluoroquinolone, macrolides and trimethoprim/sulfamethoxazole. Based on whole-genome analysis, these 21 CRKP isolates shared a common genetic structure (ISAba125-IS630-blaNDM-1-bleMBL) and harbored additional resistance determinants (blaOXA-1, blaCTX-M-15, blaSHV-11, blaSHV-67, aac(6')-Ib-cr, qnrS1, OqxA, OqxB, catB3, mph(A), sul1, and dfrA12) and mutations in the quinolone resistance-determining regions of gyrA (S83I) and parC (S80I). These isolates belonged to the ST147 and KL64 capsular types, which were carried on IncFIB replicon plasmids. The 21 CRKP strains collected from one hospital were divided into five PFGE patterns, and they were closely related with a minimum similarity value of 95.2%. These isolates were found to be highly related based on the presence of between 2 and 27 SNPs. Conclusions : These findings indicate that NDM-1-producing K. pneumoniae ST147 may have been introduced via a common source, implying nosocomial transmission; furthermore, continuous monitoring is necessary to prevent endemic transmission.