title: Potential significance of colonization with beta-lactamase-producing Haemophilus parainfluenzae in children.
abstract: Recent surveys in Vancouver showed most healthy children were colonized with beta-lactamase-producing Haemophilus parainfluenzae. Such organisms might alter the effects of penicillins on throat bacteria by local inactivation. To test this hypothesis in vitro, three isolates of beta-lactamase-producing Haemophilus parainfluenzae were each mixed on a membrane with ampicillin-sensitive strains of Haemophilus influenzae type b or group A Streptococcus pyogenes and exposed to ampicillin. When tested alone, susceptible strains were rapidly killed but when tested together with a beta-lactamase producer, they were protected, indicating efficient ampicillin degradation by Haemophilus parainfluenzae strains. If similar interactions occur in vivo, the effects of beta-lactams on throat bacteria could be significantly altered in the presence of beta-lactamase-producing Haemophilus parainfluenzae.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D002648:Child; D006190:Haemophilus / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development*; D006801:Humans; D007700:Kinetics; D010405:Penicillinase / Q000235:genetics*; D013297:Streptococcus pyogenes / Q000187:drug effects / Q000254:growth & development; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000667:Ampicillin; D010405:Penicillinase; D001618:beta-Lactamases