Whole-genome characterization and antibiotic resistance phenotype of Escherichia marmotae first isolated from Berylmys bowersi.

Escherichia marmotae was first described in 2015 as a bacterium isolated from Himalayan marmots, with recent evidence suggesting its potential to cause human diseases. This study presents the first report of E. marmotae isolation from Berylmys bowersi in Guizhou province. We conducted genetic, biochemical, and antibiotic resistance analyses on four isolates, designated as S2-2, S2-4, S2-5, and S2-6. Phylogenetic analysis based on 16S rRNA sequences revealed over 99.5% homology with E. marmotae, while pulsed-field gel electrophoresis and whole-genome sequencing confirmed genetic similarity. Gene annotation highlighted the presence of 137 virulence factors and five antibiotic resistance mechanisms, including resistance to fluoroquinolones and tetracyclines. Resistance phenotypes of 35 antibiotics showed resistance to penicillin, erythromycin, rifampin, and co-trimoxazole. The strains exhibited significant biochemical diversity, with positive results for several fermentation pathways and negative motility assays. This study underscores the emerging zoonotic potential of E. marmotae and its associated health risks in wildlife and humans.IMPORTANCEThe isolation of Escherichia marmotae from Berylmys bowersi represents a novel discovery, expanding the known host range of this bacterium. Our comprehensive analysis of its genetic, biochemical, and antibiotic resistance profiles provides critical insights into its potential as a zoonotic pathogen. The findings highlight the need for ongoing surveillance of E. marmotae, especially in wildlife populations, to assess its pathogenicity and potential threats to both animal and human health. Given its antibiotic resistance and virulence factor repertoire, E. marmotae may pose a significant public health concern in the future, warranting further investigation into its ecological and clinical relevance.