Activity of β-lactamase produced by Prevotella intermedia isolated from the human oral cavity

Abstract

We evaluated β-lactamase activity in β-lactam antibiotic-resistant strains of Prevotella intermedia by microiodometric assay of β-lactamase. β-Lactamase activity of ten oral strains was 0.004〜0.0074U/ml against ampicillin, and 0.0035〜0.0046U/ml against cefazolin. Although these enzymes resolved cephalo-ridine and cefuroxime, their resolution of imipenem, latamoxef and aztreonam was different for each strain. Penicillin G and cephalexin induced production of β-lactamase in one strain tested, but not in two others. We concluded that constitutive β-lactamase produced by β-lactam antibiotic-resistant strains of P. intermedia plays an important role in this resistance mechanism, and that these enzymes are oxyiminocephalo-sporinase.