Emergence of KL57 hypervirulent Klebsiella pneumoniae in Wuxi, China: Genomic insights into virulence plasmid evolution and blaKPC-2-bearing IncFIIK34 plasmid transmission
Year: 2025
Type: article
Abstract: KL57 Klebsiella pneumoniae ( K. pneumoniae ) is an emerging serotype with epidemiological characteristics and pathogenic mechanisms that remain incompletely understood. This study comprehensively analyzed the genomic features of KL57 K. pneumoniae strains isolated in Wuxi from 2016 to 2023, and investigated the global molecular epidemiology and population dynamics of KL57 K. pneumoniae . From January 2016 to December 2023, 17 KL57 K. pneumoniae isolates were collected from various clinical specimens at the Wuxi No.2 People's Hospital, Jiangsu Province, China. Antimicrobial susceptibility testing (AST), whole-genome sequencing (WGS), and bioinformatics analysis including evaluation of virulence genes, resistance genes, and plasmid replicon types were performed on these strains. To elucidate the genetic relationships and global distribution of the KL57 K. pneumoniae , phylogenetic trees were constructed through comparative analyses of our KL57 strains alongside those obtained from public databases. Additionally, the distribution patterns of serotypes and carbapenemase genes among these strains were examined. Seventeen KL57 K. pneumoniae strains were categorized into four distinct sequence types (STs), with ST412 being the most prevalent in Wuxi, and ST2846, which was identified for the first time. Analysis of virulence genes indicated KL57 K. pneumoniae isolates often express multiple virulence factors. Antimicrobial resistance profiling revealed that only one ST218 isolate contained the bla KPC-2 gene, which was located on an IncFII K34 plasmid. Geographically, ST412, ST218, and ST592 were the main predominant epidemic sequence types of the KL57 K. pneumoniae . A global analysis indicated that KL57 carbapenem-resistant K. pneumoniae (CRKp) strains predominantly harbored the bla NDM-1 , bla OXA-48 , bla KPC-2 , and bla OXA-181 genes. Furthermore, phylogenetic analysis demonstrated significant diversity in the sequence types of KL57 K. pneumoniae strains across continents, with notable variations even between countries. Our study corroborates the widespread occurrence of the ST412 KL57 K. pneumoniae in China and identifies a specific strain harboring the IncFII K34 resistance plasmid. Additionally, the KL57 CRKp strain carries a variety of carbapenemase genes, and some of these strains simultaneously harbor multiple such genes. Our findings suggest that this subtype demonstrates enhanced resistance adaptability and may facilitate the dissemination of drug resistance through horizontal gene transfer. Consequently, it is necessary to develop more targeted surveillance strategies that focus on resistance gene characteristics and prevalent subtypes.
Authors: Yutong Liu, Lin Wan, Xiong Li, Yingshun Zhou, Renjing Hu
Language: English
Subfield: Molecular Medicine
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,410
OpenAlex ID: W4416543015