Effect of β-lactamase inhibitors on the β-lactamase activity of Prevotella intermedia from odontogenic infections

Abstract

β-Lactamase is closely related to the mechanism of β-lactam resistance in Prevotella intermedia from odontogenic infections. We studied the efficacy of β-lactamase inhibitors to design compounds of β-lactams and β-lactamase inhibitors with the most potent activity against β-lactamase producing clinical isolates of Prevotella intermedia. The minimum inhibitory concentration (MIC) of the β-lactamase inhibitors clavulanic acid (CVA), sulbactam (SBT) and tazobactam (TAZ) was in the range 0.06〜8.00μg/ml against fifteen β-lactamase producing clinical isolates of Prevotella intermedia. In penicillin G with 0.5〜2.0μg/ml of β-lactamase inhibitors, the efficacy of the inhibitors that caused a marked reduction in growth of β-lactamase producing clinical isolates of Prevotella intermedia was 79〜94% for β-lactamase producing the clinical isolates for CVA, 73〜100% for SBT, and 86〜100% for TAZ. Combinations of each inhibitor and cephalexin, cefteram, cefaclor, ampicillin, cefazolin, and piperacillin were also effective β-lactamase inhibitors against clinical isolates. We found the therapeutic efficacy of combinations of β-lactams and β-lactamase inhibitors was stronger than that of penicillins and cephems against odontogenic infections with β-lactamase producers of prevotella intermadia.