Beta-lactamase-producing isolates of Bacteroides species from children.

Two hundred twenty-four isolates of Bacteroides sp. were recovered from recurrently inflamed tonsils, infected peritoneal fluid, abscesses, wounds, and burns of hospitalized children. Isolates were examined for beta-lactamase production by the chromogenic cephalosporin analog 87/312 methodology. Altogether, 119 isolates were beta-lactamase producers. Of these, 53 were in the B. fragilis group, 28 were in the B. melaninogenicus groups, 12 were B. oralis, 4 were B. ruminicola subsp. brevis, and 22 were Bacteroides sp. Of 28 beta-lactamase-producing strains of B. melaninogenicus, 25 were recovered from tonsils. These observations indicate that in pediatric patients there is a significant incidence of beta-lactamase producers among anaerobes other than B. fragilis.