Epidemiology-guided discovery of a K1-specific lytic phage with therapeutic potential against ST23-K1 multidrug-resistant hypervirulent Klebsiella pneumoniae.

Phage therapy has emerged as a promising alternative for combating multidrug-resistant hypervirulent Klebsiella pneumoniae (MDR-hvKP) infections. Recent advances suggest that tailoring phage cocktails based on genomic surveillance of circulating strains might yield more effective regimens (Koncz et al., 2024). Here, we combined publicly available epidemiological records with regional strain analysis to examine the distribution of the ST23-K1 lineage and to place the selected target in genomic and clinical context. Among the 227 isolates in our Henan collection, ST23-K1 accounted for 11.01% of isolates. We isolated a novel lytic phage, vB_KpnS_P10HW, from urban sewage using a clinically representative high-risk ST23-K1 MDR-hvKP strain, KH1127-5, as the host. vB_KpnS_P10HW exhibited lytic activity against K1-type K. pneumoniae isolates across four sequence types. The phage displayed rapid adsorption (80% within 10 min), a short latent period (5 min), and remarkable stability across temperature (4-60 °C) and pH (4-10) ranges. Whole-genome sequencing revealed a 49,682 bp linear dsDNA genome devoid of lysogeny, virulence, or antibiotic resistance genes. Phylogenomic analysis placed vB_KpnS_P10HW within the family Drexlerviridae, genus Webervirus. Functionally, vB_KpnS_P10HW rapidly reduced viable bacterial cells within 30 min at high multiplicities of infection and effectively disrupted preformed biofilms in a dose-dependent manner. In vivo, phage administration increased the survival rates in both Galleria mellonella and mouse infection models. These results support vB_KpnS_P10HW as a genetically safe and promising therapeutic candidate against clinically relevant ST23-K1-associated MDR-hvKP and suggest that integrating genomic epidemiological context with phage characterization may help prioritize regional targets for precision phage therapy against K. pneumoniae.