Absence of co-localization between pathovar-associated virulence factors and extended-spectrum β-lactamase (blaCTX-M) genes on a single plasmid.

Extended-spectrum β-lactamases (ESBLs) were reported in virulent food-borne Escherichia coli clones, and numerous genes encoding ESBLs and virulence factors (VFs) are plasmid-mediated. We investigated the plasmidic co-localization of ESBL genes and pathovar-associated VF genes isolated in 18 E. coli isolates from faecal samples of diseased cattle.