Prevalence of Clinical Isolates of Escherichia coli Producing Inhibitor-Resistant β-Lactamases at a University Hospital in Barcelona, Spain, over a 3-Year Period

About 7% of 7,252 nonduplicated clinical Escherichia coli strains from a Spanish hospital showed reduced susceptibility to amoxicillin-clavulanate. Of these, 0.37% produced the IRTs TEM-30, TEM-31, TEM-33, TEM-34, TEM-37, TEM-40, TEM-51, and TEM-54; 5.3% were probable class C beta-lactamase overproducers; 0.8% were probable TEM-1 hyperproducers; 0.18% produced OXA-30; 0.15% overexpressed SHV-1; and 0.03% produced a PSE-1 enzyme.