IncFII Conjugative Plasmid-Mediated Transmission of bla NDM-1 Elements among Animal-Borne Escherichia coli Strains

This study aims to investigate the prevalence and transmission dynamics of the bla NDM-1 gene in animal Escherichia coli strains. Two IncFII bla NDM-1 -encoding plasmids with only minor structural variation in the MDR region, pHNEC46-NDM and pHNEC55-NDM, were found to be responsible for the transmission of bla NDM-1 in these strains. The bla NDM-1 gene can be incorporated into plasmids and stably inherited in animal-borne E. coli strains that can be maintained in animal gut microflora even without carbapenem selection pressure.