Epidemiological and genomic profiles of NDM-1-Producing ST25-KL2 carbapenem-resistant Klebsiella pneumoniae among pediatric patients in Hangzhou, China

The emergence and dissemination of carbapenem-resistant Klebsiella pneumoniae (CRKP) within healthcare settings is recognized as an “urgent threat” to public health. CRKP infections in pediatric patients exhibit distinct genetic and phenotypic features compared to those observed in adult patients. This study performed whole-genome sequencing on 92 CRKP isolates collected from pediatric patients at Children’s Hospital, Zhejiang University School of Medicine over a 6-year period (2019–2024), and systematically characterized the profiles of antimicrobial resistance genes, virulence factors, capsular types, and antimicrobial resistance (AMR) prevalence. Ninety-two CRKP isolates were collected, NDM-type was the predominant carbapenemase (64/92). Capsule typing analysis demonstrated that KL2 was the most prevalent type, comprising 43.48% (40/92) of all isolates. All KL2 isolates harbored the bla NDM−1 gene and exhibited resistance to ceftazidime/avibactam (CZA). Comparative analysis of the plasmid genomic sequences of ST25-KL2 CRKP with those of all available K. pneumoniae isolates in the National Center for Biotechnology Information (NCBI) database revealed that the DY1928 strain, isolated from Hangzhou, Zhejiang Province, exhibited high sequence homology to the plasmid genomes identified in this study. In addition to harboring a conservative structural sequence ( bla NDM−1 - ble - trpF - dsbD ) located downstream of the bla NDM−1 gene, the strain also carries the resistance genes bla CTX−M−104 , bla TEM−1−B , and rmtB . We performed genomic analysis and epidemiological studies on the CRKP among pediatric patients in China over six years and report the emergence of a specific clone. Our research results indicate that clonal dissemination of ST25-KL2, which requires enhanced monitoring of this situation in the future.