title: In vitro activity of modern penicillins and cephalosporins against enterococci.
abstract: The in vitro activity of nine penicillin and cephalosporin antibiotics against enterococci was compared by MIC determination and killing curve experiments. To inhibit 90% of the 143 clinical isolates tested the following drug concentrations were required: mezlocillin, 1--2 micrograms/ml; azlocillin, 2 micrograms/ml; piperacillin, 4 micrograms/ml; cefazedone, 16 micrograms/ml; cefazolin and cefoperazone, 32 micrograms/ml; ticarcillin, 64 micrograms/ml. Cefotaxime and lamoxactam proved to be almost ineffective at 128 micrograms/ml which was the highest concentration tested. In killing curve experiments a reduction of viable cell count by 2--3 logs was achieved with all antibiotics except cefotaxime and lamoxactam. In general, the acylureido-penicillins exhibited a better bactericidal activity than the cephalosporins.
mesh_terms: D002511:Cephalosporins / Q000494:pharmacology*; D003470:Culture Media; D013293:Enterococcus faecalis / Q000187:drug effects*; D005260:Female; D005836:Genitalia, Female / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D010406:Penicillins / Q000494:pharmacology*; D014552:Urinary Tract Infections / Q000382:microbiology
chemical_list: D002511:Cephalosporins; D003470:Culture Media; D010406:Penicillins