Emergence and regional evolution of Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae ST11 in China.

OBJECTIVES: Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-KP) sequence type (ST) 11 has emerged as a significant public health threat in China, yet its endemic population and evolutionary dynamics remain incompletely understood. To address this, we investigated the national distribution and local evolution of KPC-KP ST11 in China. METHODS: Our analysis included 4,262 KPC-KP ST11 genomes, comprising 56 isolates from a Guangdong hospital and 4,206 publicly available genomes. The genomic analysis encompassed population structure, genome annotation, and evolutionary dynamics, and was conducted on all sequenced genomes. RESULTS: Using a threshold of 10 core genome allelic differences, hierarchical clustering revealed 456 lineages, highlighting substantial regional-specific distribution. The majority of the genomes carried the blaKPC-2 gene, which frequently co-occurs with resistance genes for aminoglycosides, fluoroquinolones, and fosfomycin. Beyond antibiotic resistance, plasmids from KPC-KP ST11 also harbored genes associated with survival under heavy metal stress and hypervirulence. Phylogenetic dating placed the most recent common ancestor of all isolates at approximately 2001. The evolutionary model estimated that the Guangdong endemic lineages emerged from Zhejiang around 2016, followed by virulence plasmid acquisition. CONCLUSION: In conclusion the evolutionary trajectories of KPC-KP ST11 offer valuable insights into localized persistence and intermittent dissemination, enhancing our understanding of its regional spread and adaptation.