title: Different penicillin sensitivities between capsulated strains of Staphylococcus aureus and their non-capsulated variants.
abstract: Four capsulated strains of Staphylococcus aureus were penicillin sensitive and qualitatively negative for penicillinase; however, their non-capsulated variants were all resistant to penicillin and positive for penicillinase. With a capsulated strain, remarkably low penicillinase was detected within cells when the organisms were broken by sonic oscillation and the majority of the remarkably higher penicillinase activity in its non-capsulated variant was found in the cell surface fraction. When the capsulated strain was cultured in plain brain heart infusion broth at 43 degrees C for 72 h, the majority of the organisms did not produce capsules and significantly higher penicillinase activity was found in the culture supernatant.
mesh_terms: D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000494:pharmacology*; D010405:Penicillinase / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism
chemical_list: D010405:Penicillinase; D010400:Penicillin G