Genomic characterization of ST11-KL19 carbapenem-resistant Klebsiella pneumoniae carrying dual carbapenemases and hypervirulence-associated markers

OBJECTIVES: The global convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae poses a critical public health threat. While ST11-KL64 has historically dominated in China, the evolutionary dynamics driving the emergence of novel high-risk sublineages remain poorly understood. METHODS: We analysed 304 non-duplicate carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates collected in Zhejiang Province, China, during 2024-2025 using antimicrobial susceptibility testing, whole-genome sequencing, plasmid analysis, and phylogenetic reconstruction. Publicly available genomes were incorporated for comparative genomic and phylogenetic analyses. RESULTS: were linked to IncFII(pHN7A8)-IncR-like and IncN-like plasmids, respectively. Correlation analyses demonstrated coordinated accumulation of resistance and virulence determinants specifically in rmpA-intact ST11-KL19 isolates. In the global ST11-KL19 phylogeny, the C2e subcluster showed a higher burden of antimicrobial resistance genes and hypervirulence-associated markers than other subclusters. CONCLUSIONS: ST11-KL19 represents a CRKP background with increased local detection and frequent carriage of dual carbapenemases, hypervirulence-associated markers, and resistance to last-line agents. These findings support enhanced genomic surveillance of ST11-KL19, while multicentre longitudinal studies and functional assays are required to define its transmissibility, virulence phenotype, and evolutionary trajectory.