title: Combined antibacterial activity of amoxicillin with clavulanic acid against ampicillin-resistant strains.
abstract: Strains of bacteria resistant to beta-lactam antibiotics have been increasing in number and are becoming troublesome in clinical medicine. The in vitro antibacterial activity of amoxicillin combined with clavulanic acid was determined on selected ampicillin-resistant clinical isolates. Synergistic effects were produced by amoxicillin with clavulanic acid against ampicillin-resistant strains of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris, and Bacteroides fragilis. Inhibition of the beta-lactamases produced by the ampicillin-resistant strains was confirmed, especially against the penicillinases mediated by the R factor and the cephalosporinases produced by P.vulgaris and B. fragilis. The inhibitory effect of clavulanic acid against beta-lactamases was irreversible because of the high affinity of clavulanic acid to the enzymes.
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology*; D000667:Ampicillin / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000201:enzymology; D019818:Clavulanic Acid; D004357:Drug Synergism; D007700:Kinetics; D010403:Penicillin Resistance; D065093:beta-Lactamase Inhibitors; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D065093:beta-Lactamase Inhibitors; D047090:beta-Lactams; D019818:Clavulanic Acid; D000667:Ampicillin; D000658:Amoxicillin