Occurrence of ST23 complex phylogroup A Escherichia coli isolates producing extended-spectrum AmpC beta-lactamase in a French hospital.

ABSTRACT

Extended-spectrum AmpC beta-lactamase (ESAC) Escherichia coli producers were investigated over a 5-year period. Eleven isolates presenting a strong ampC promoter and different strategic AmpC mutations, including two newly described modifications (A292V and an L-A-A insertion at 295), were characterized. All the isolates belonged to phylogenetic group A and to the ST23 complex.