title: Characterization and comparison of two penicillinase-producing strains of Streptococcus (Enterococcus) faecalis.
abstract: We identified two beta-lactamase-positive enterococci. One strain was high-level (MIC, greater than 2,000 microgram/ml) gentamicin resistant; the other was not (MIC, 12.5 microgram/ml). beta-Lactamase production was extrachromosomally mediated in both strains, and both strains showed an inoculum effect reversed by beta-lactamase inhibitors. The strain lacking high-level gentamicin resistance showed synergistic killing with a combination of penicillin, clavulanic acid, and gentamicin.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D019818:Clavulanic Acid; D002969:Clavulanic Acids / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D004357:Drug Synergism; D013293:Enterococcus faecalis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D005839:Gentamicins / Q000494:pharmacology; D010405:Penicillinase / Q000096:biosynthesis*; D010406:Penicillins / Q000494:pharmacology; D010641:Phenotype; D011815:R Factors; D013407:Sulbactam / Q000494:pharmacology; D065093:beta-Lactamase Inhibitors
chemical_list: D002969:Clavulanic Acids; D005839:Gentamicins; D010406:Penicillins; D065093:beta-Lactamase Inhibitors; D019818:Clavulanic Acid; D000667:Ampicillin; D010405:Penicillinase; D013407:Sulbactam