Emergence of ST11 Klebsiella pneumoniae co-carrying blaKPC-2 and blaIMP-8 on conjugative plasmids.

UNLABELLED: Klebsiella pneumoniae is a major pathogen with substantial antimicrobial resistance driven by β-lactamase production. The co-existence of carbapenemase genes blaKPC-2 and blaIMP-8 in the prevalent K. pneumoniae clone is rare and poses significant clinical challenges in China. In this study, we report the first identification of a clinical ST11 K. pneumoniae strain Kp4874, isolated from a hospitalized patient in China, co-carrying blaKPC-2 on a ~134 kb IncFII/IncR hybrid plasmid and blaIMP-8 on a ~75 kb untypable plasmid. Whole-genome sequencing revealed key insertion sequences, including TnAs1 and IS26, facilitating horizontal transfer of these resistance genes. Conjugation experiments confirmed the high transferability of both plasmids, particularly the blaKPC-2 plasmid. Despite harboring multiple virulence genes, the strain's clinical threat stems primarily from its multidrug-resistant profile. This study highlights the potential for rapid dissemination of such strains in healthcare settings and underscores the critical need for robust surveillance and infection control measures.

IMPORTANCE

This study is the first to report the co-existence of blaKPC-2 and blaIMP-8 in an ST11 Klebsiella pneumoniae strain, underscoring the clinical threat posed by these carbapenemase genes. The identification of blaKPC-2 on an IncFII/IncR hybrid plasmid, coupled with the successful conjugation of both resistance genes, highlights the significant potential for horizontal gene transfer and multidrug-resistant dissemination. These findings advance our understanding of plasmid-mediated resistance and emphasize the urgent need for enhanced monitoring and infection control strategies to mitigate the spread of such high-risk strains.