Transfer Potential of Plasmids Conferring Extended-Spectrum-Cephalosporin Resistance in Escherichia coli from Poultry.

strains resistant to extended-spectrum cephalosporins (ESC) are widely distributed in Norwegian broiler production, and the majority harbor transferable IncK or IncI1 plasmids carrying Persistent occurrence in broiler farms may occur through the survival of ESC-resistant strains in the farm environment, or by transfer and maintenance of resistance plasmids within a population of environmental bacteria with high survival abilities. The aim of this study was to determine the transferability of two successful -carrying plasmids belonging to the incompatibility groups IncK and IncI1 into and species recipients. Initially, conjugative plasmid transfer from two donors to potential recipients was tested in an agar assay.