Induction of Prevotella intermedia β-lactamase by various β-lactam antibiotics

Abstract

Some strains of Prevotella intermedia isolated from oral infections show resistance to β-lactam antibiotics, and produce β-lactamase. We examined the induction of P. intermedia β-lactamase by various β-lactam antibiotics frequently administered for oral infections using P. intermedia MA1-V2 from a closed dentoalveolar abscess. β-Lactamase activity for the substrates cefazolin (CEZ) and ampicillin (ABPC) was 2.27 and 0.42 U/mg protein after exposure without drugs (control), respectively. After exposure to 1/8〜1/128 MIC of ten β-lactam antibiotics for 4h, enzyme activity of CEZ with treatment of latamoxef and cefaclor (CCL) was increased to the value without drugs, and for 15h, this activity of CEZ with exposure of cephalexin (CEX), piperacillin and imipenem was higher than that of the control. Enzyme activity for ABPC was increased after exposure to penicillin G, ABPC and CEX for 15h compared with no drug exposure. These results suggest that P. intermedia β-lactamase was induced by oral drugs such as ABPC, CCL and CEX.