Abstract
Introduction: Klebsiella variicola, a member of Klebsiella pneumoniae complex, has emerged as an opportunistic pathogen for human infection; however, antimicrobial resistance and hypervirulent characteristics of K. variicola have rarely been investigated in South Korea. Methods: We analyzed 76 clinical K. variicola isolates collected from 12 hospitals between September 2022 and October 2023. Bacterial identification was performed by MALDI-TOF MS. Antimicrobial susceptibility was tested by disk diffusion tests. Resistance determinants and virulence traits were investigated, and whole-genome sequencing was performed for hypermucoviscous or carbapenem-resistant K. variicola isolates. Results: Most (89.5%, 68/76) were susceptible to all 18 antimicrobials tested in this study, and 3 isolates harbored bla(CTX-M-15). One isolate carried bla(KPC-2) on its IncX3 plasmid, which is closely related to carbapenem-resistant K. pneumoniae plasmids. Capsular typing revealed 51 wzi allelic types. Ten isolates showed mucoid phenotype, mainly with KL60 and KL61. Conclusions: This study reveals relatively low resistance rates in K. variicola strains but the presence of multidrug-resistant and hypermucoviscous K. variicola strains. In addition, the evidence of interspecies dissemination of bla(KPC-2) highlights the need for continuous genomic surveillance.