Characterization of a beta-lactamase from Pasteurella multocida.

A bovine strain of Pasteurella multocida was found to produce a beta-lactamase. The minimal inhibitory concentrations of amoxicillin (128 mg/l) and ticarcillin (512 mg/l) were high for this strain. The enzyme was periplasmic and produced constitutively, and there was no obvious permeability barrier. This enzyme had a TEM-substrate profile, and no inhibition was detected with antisera (anti-TEM-1, anti-TEM-2). The apparent isoelectric point was estimated at 8.8.