Emergence of blaNDM-carrying Escherichia coli ST167 isolate in rural communities in western Shandong Province, China

Objectives This study aimed to investigate the prevalence, genomic features, and plasmid characteristics of carbapenem-resistant Escherichia coli (CR-EC) harboring bla NDM within a "One Health" framework in rural communities of western Shandong Province, China, to assess potential public health risks. Methods A cross-sectional sampling of human, animal, and environmental sources was conducted. Recovered CR-EC isolates underwent antimicrobial susceptibility testing, whole-genome sequencing, and phylogenetic analysis. Plasmid genetic structure was characterized, and conjugation assays were performed to evaluate the transferability of bla NDM -carrying plasmids. Results Among 26 CR-EC isolates, bla NDM-5 was predominant (84.6%). All strains were extensively drug-resistant. Notably, 10 of 11 isolates belonging to the high-risk global clone ST167 originated from asymptomatic human carriers, suggesting community transmission. Genomic analysis identified IncF-type plasmids carrying bla NDM with >99% identity to plasmids from clinical strains in Australia and Germany. Conjugation confirmed plasmid transferability. Phylogenetic clustering among human isolates indicated clonal spread, with potential zoonotic links. Multiple virulence genes (e.g., astA, iuc, fim ) were detected. The presence of bla NDM in wastewater highlighted environmental dissemination. Conclusions The findings reveal the concerning emergence and dissemination of high-risk CR-EC clones in a rural setting, facilitated by mobile genetic elements across human, animal, and environmental reservoirs. This underscores an urgent need for integrated genomic surveillance and targeted interventions to mitigate the spread of CR-EC in community ecosystems.