title: Emergence of beta-lactamase producing anaerobic bacteria in the tonsils during penicillin treatment.
abstract: The emergence of beta-lactamase producing bacteria in the microflora in the oropharyngeal cavity was studied in ten healthy volunteers treated with 1 g phenoxymethylpenicillin b.i.d. for ten days. Beta-lactamase activity in saliva was also investigated. A significant increase in the number of beta-lactamase producing strains of Bacteroides species and Fusobacterium nucleatum was observed. One beta-lactamase producing Staphylococcus aureus strain was recovered in one of the volunteers before the penicillin administration started and three Staphylococcus aureus strains produced beta-lactamase after ten days of antibiotic treatment. Beta-lactamase-production in Haemophilus influenzae, Haemophilus parainfluenzae or Branhamella catarrhalis was not observed before, during or after the antibiotic treatment. Beta-lactamase activity was noted in the broth cultures from one volunteer colonized with a beta-lactamase producing Escherichia coli strain. Beta-lactamase activity in saliva was observed in all volunteers, the activity increasing significantly in parallel to the increase of beta-lactamase producing bacterial strains. Beta-lactamase activity in saliva was completely inhibited in vitro by clavulanic acid and p-chloromercurbenzoate and about 70-80 per cent of the activity was inhibited by cefoxitin. The increase of beta-lactamase producing bacteria in the oropharynx as a consequence of penicillin treatment raises doubt as to whether penicillin is the drug of choice in the treatment of tonsillitis caused by group A streptococci when previous treatment has failed.
mesh_terms: D000328:Adult; D001421:Bacteria, Anaerobic / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D001439:Bacteroides / Q000201:enzymology; D004926:Escherichia coli / Q000201:enzymology; D005260:Female; D005673:Fusobacterium / Q000201:enzymology; D006801:Humans; D008297:Male; D009960:Oropharynx / Q000382:microbiology; D014066:Palatine Tonsil / Q000382:microbiology*; D010404:Penicillin V / Q000494:pharmacology*; D012463:Saliva / Q000201:enzymology; D013211:Staphylococcus aureus / Q000201:enzymology; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D001618:beta-Lactamases; D010404:Penicillin V