Molecular Epidemiology of Klebsiella pneumoniae Based on Whole-Genome Sequencing Among Hospitalized Patients in Huzhou, China: A 6-Year Surveillance Study, 2020–2025

Klebsiella pneumoniae has become a critical global public health threat due to the rapid spread of hypervirulent and multidrug-resistant clones. A total of 205 non-duplicate K. pneumoniae isolates were collected from seven hospitals in Huzhou, China, between January 2020 and December 2025. Antimicrobial susceptibility testing, the string test, whole-genome sequencing, and bioinformatics analysis were applied to determine resistance phenotypes, virulence features, multilocus sequence types (STs), capsular types, plasmid replicons, and phylogenetic relationships. Of the 205 isolates, 180 (87.80%) were identified as hypervirulent K. pneumoniae (hvKP), with ST23-K1 and ST86-K2 being the dominant clones. This unusually high hvKP detection rate may be attributable to our study population composition, with patients aged ≥ 60 years accounting for 77.08% of all subjects. High resistance rates were observed for ampicillin (73.66%), tetracycline (27.32%), and trimethoprim–sulfamethoxazole (25.85%). Eleven isolates carried blaKPC-2 and one harbored mcr-1, displaying corresponding drug-resistant phenotypes. The isolates exhibited high genetic diversity with 62 STs, 25 capsular types, and 38 plasmid replicons. Co-occurrence of virulence and resistance determinants was commonly detected. Five genetic lineages (A to E) were classified among all isolates, and no epidemiological outbreak clusters were detected in our study. The hvKP is highly endemic in Huzhou, while local K. pneumoniae isolates show high resistance to conventional antibiotics but remain largely susceptible to last-resort antimicrobials. The coexistence of hypervirulence and antimicrobial resistance underscores the urgent need for continuous genomic surveillance to curb the dissemination of high-risk clones.