Genomic epidemiology reveals inter-regional dissemination of multidrug-resistant Klebsiella pneumoniae clones in Chinese cattle farms

The extensive use of antibiotics in animal husbandry intensifies the dissemination of resistant bacteria. This study provides a comprehensive genomic epidemiological analysis of bovine-origin Klebsiella pneumoniaeacross China to assess its public health threat.A total of 182 K. pneumoniaeisolates recovered from bovine feces across 13 provinces were subjected to antimicrobial susceptibility testing and whole-genome sequencing. We integrated phylogenomic analysis with core-genome SNP (cgSNP) profiling to track clonal transmission networks at a national scale.Isolates exhibited prevalent multidrug resistance; notably, 54.95% and 21.98% were resistant to imipenem and third-generation cephalosporins, respectively. Sequencing identified a diverse acquired resistome of 84 gene families, dominated by blaSHVsubtypes. A significant divergence between phenotypic carbapenem resistance and genomic content emerged: classical carbapenemases (blaNDM, blaKPC) were entirely absent, indicating a non-canonical resistance architecture in bovine strains. Genomes exhibited high diversity (67 STs), with ST1537, ST37, and ST7133 emerging as dominant lineages. Employing a stringent ≤18 cgSNP threshold, 72 isolates formed four high-confidence inter-provincial transmission clusters. Specifically, a low-divergence ST37 cluster harboring blaSHV-27was identified as a key driver of long-distance "silent" dissemination across geographically distant provinces.These findings provide robust genomic evidence that the Chinese bovine industry serves as a stabilized reservoir for clinically relevant MDR K. pneumoniaelineages. The extensive inter-regional transmission of high-risk clones like ST37 underscores a critical biosecurity gap, necessitating integrated genomic surveillance within the "One Health" framework to mitigate zoonotic spillover.