Genomic and phylogeographical analysis revealed CTX-M-55 producing ST10 and ST2325 clones of One Health concern from dairy farm waste in Gansu, China.

Extended-spectrum beta-lactamase (ESBL)-producing resists broad-spectrum cephalosporins, considered as a critical priority pathogen, and its presence in animals, humans, and the environment highlights its significance as a One Health issue. Dairy farm waste is a potential environmental contaminant and can serves as a significant reservoir for the emergence and spread of ESBL-producing , which belongs to One Health clones and poses a serious global threat. This study aimed to investigate the occurrence and genomic characteristics of ESBL-producing clones of One Health concern from dairy farm waste in Gansu, China. In this study, we isolated and characterized two CTX-M-55 ESBL-producing strains, ZYX8158 and ZYS8091, which belong to One Health clones. The genomic analysis revealed a large resistome, mobilome, virulome, and plasmidome was acquired by both ESBL-producing strains. The genome-based typing revealed that ZYX8158 and ZYS8091 belonged to globally disseminated clones ST10 (O73:H31 serotype) and ST2325 (O66:H25 serotype), respectively. Phylogeographical analysis revealed both strains as potential One Health clones due to their clustering with related strains isolated from animal, human, and environmental sources, regardless of geographical boundaries, indicating their zoonotic potential and clonal spread in the One Health sector. This study highlights that dairy farm waste can be a potential source of the emergence and dissemination of One Health clones of critical priority ESBL-producing in One Health settings, which demands continuous and integrated genomic surveillance for comprehensive knowledge and mitigation strategies.