Characterization of Antimicrobial Resistance and Hypervirulent Traits of Klebsiella variicola Isolates Collected in South Korea

<b>Introduction</b>: <i>Klebsiella variicola</i>, a member of <i>Klebsiella pneumoniae</i> complex, has emerged as an opportunistic pathogen for human infection; however, antimicrobial resistance and hypervirulent characteristics of <i>K. variicola</i> have rarely been investigated in South Korea. <b>Methods</b>: We analyzed 76 clinical <i>K. variicola</i> 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 <i>K. variicola</i> isolates. <b>Results</b>: Most (89.5%, 68/76) were susceptible to all 18 antimicrobials tested in this study, and 3 isolates harbored <i>bla</i>_CTX-M-15. One isolate carried <i>bla</i>_KPC-2 on its IncX3 plasmid, which is closely related to carbapenem-resistant <i>K. pneumoniae</i> plasmids. Capsular typing revealed 51 <i>wzi</i> allelic types. Ten isolates showed mucoid phenotype, mainly with KL60 and KL61. <b>Conclusions</b>: This study reveals relatively low resistance rates in <i>K. variicola</i> strains but the presence of multidrug-resistant and hypermucoviscous <i>K. variicola</i> strains. In addition, the evidence of interspecies dissemination of <i>bla</i>_KPC-2 highlights the need for continuous genomic surveillance.