Antimicrobial resistance testing of verocytotoxin-producing Escherichia coli and first description of TEM-52 extended-spectrum β-lactamase in serogroup O26.

We have investigated the antimicrobial resistance of verocytotoxin-producing Escherichia coli (VTEC) strains isolated from humans, animals, food, and the environment in Belgium. Resistance was more frequent in non-O157 strains from humans than in O157 strains from humans or other sources, and among non-O157 VTEC strains, intimin-positive strains were more resistant than intimin-negative strains. We also report the first VTEC strain producing an IncI1 extended-spectrum β-lactamase encoded by plasmid-borne bla(TEM-52); this β-lactamase was previously associated with Salmonella enterica and E. coli isolates from different origins.