Potential pathogenicity and host range of extended-spectrum beta-lactamase-producing Escherichia coli isolates from healthy poultry.

Thirty of 33 epidemiologically unrelated extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates from healthy poultry lacked the virulence genes commonly associated with human-pathogenic strains. The main zoonotic risk is associated with the broad host range of avian E. coli belonging to sequence type complex 10 and of IncN and IncI1 plasmids carrying bla(CTX-M) or bla(SHV).