In vitro Activity of Loracarbef against TEM Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains andIts Interaction with the Enzymes

Abstract

The in vitro activity of loracarbef was evaluated against Escherichia coli strains producing TEM extended-spectrum β-lactamases (ESBLs). The MICs of loracarbef were lower than those of cefaclor and cephalothin. The antibiotic was active (MICs ≤2 mg/l) against strains producing TEM-6, TEM-8, TEM-10, TEM-16, TEM-26 and TEM-28 β-lactamases. The MICs for TEM-3-, TEM-5- and TEM-24-producing strains were higher (≥ 16 mg/l). Hydrolysis studies indicated that the latter β-lactamases inactivated loracarbef more efficiently than the remaining TEM-type ESBLs examined.