Klebsiella pneumoniae is an opportunistic pathogen that can cause both hospital- and community-acquired infections worldwide[1]. Based on their pathogenicity, K. pneumoniae can be broadly classified into classical K pneumoniae (cKp) and hypervirulent K. pneumoniae (hvKp)[2]. hvKp strains are distributed across multiple clonal groups (CGs) and sequence types (STs), including CG23/ST23, CG65/ST65, and CG86/ST86, and are associated with various capsular locus (KL) types such as KL1, KL2, KL5, and KL57[3]. Among these, ST23, which represents the dominant lineage within CG23, has been extensively documented for its strong association with the hypervirulent phenotype on a global scale.

Since its initial report in the 1980s, ST23 hvKp strains have been linked with severe infections, such as liver abscesses and endophthalmitis, which frequently lead to poor clinical outcomes[4]. ST23 is generally regarded as the prototypical hvKp lineage. Reports of multidrug-resistant (MDR) ST23 strains, particularly those harboring carbapenemase genes, remain rare. However, on July 31, 2024, the World Health Organization (WHO) released a report summarizing the global status of hvKp infections, with particular emphasis on the growing threat of antimicrobial resistance (AMR)[5]. Similarly, the European Centre for Disease Prevention and Control (ECDC) recently drew attention to the MDR ST23 lineage, highlighting its rapid evolution in coproducing carbapenemases and its capacity to acquire multiple carbapenemase genes[6], including blaKPC-2, blaNDM-1 and blaOXA-48. The rise of carbapenem resistance in hvKp ST23 strains is associated with high mortality rates and presents a distinct disease spectrum compared with cKp infections. This significant burden emphasizes the urgent need for research on virulence and AMR mechanisms in K. pneumoniae. However, the detailed genomic changes driving these adaptations remain poorly understood.

In this study, we expand prior investgations by performing a comprehensive genomic analysis of all publicly available ST23 genomes from the NCBI genome database (n = 1,622) to investigate the global epidemiological trends of this high-risk clone. We analyzed the resistome, virulome, plasmid content, and phylogenetic relationships of these isolates, with a particular focus on the newly emerging carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKp) ST23 strains. Overall, our study reveals the genetic structure and distinct geographical distribution of the newly emerged ST23-KL57 lineage carrying dual carbapenemases, demonstrating the ongoing evolution of K. pneumoniae. These findings highlight the urgent need for enhanced global surveillance to detect emerging threats and monitor potential interspecies transmission of virulence and antimicrobial resistance determinants.