[Bactericidal activity of combinations of ticarcillin-clavulanic acid or other beta-lactams (amoxicillin, piperacillin-tazobactam, ticarcillin) with gentamicin against Enterococcus faecalis and E. faecium].
MICs of amoxicillin, piperacillin-tazobactam, ticarcillin and ticarcillin-clavulanic acid were determined against 52 clinical strains of E. faecalis and E. faecium. Modal MICs (mg/l) of these antibiotics were 1, 4, 64 and 64, respectively. Bactericidal activity of the beta-lactams was tested at two concentrations (1/2 MIC and 100 mg/l) alone or combined with gentamicin (4 mg/l) against 10 clinical strains of Enterococcus spp. Activity of ticarcillin was not modified by the addition of clavulanic acid (4 mg/l). Time-kill curves showed that all beta-lactams at 100 mg/l were bactericidal after 18 h of incubation (decrease in bacterial counts > or = 3 log10 CFU/ml) against 6 strains of E. faecalis, with MICs of amoxicillin at 1 mg/l and 2 strains of E. faecium with MICs of amoxicillin at 1 and 2 mg/l. Addition of gentamicin resulted in a bactericidal effect at 3 or 6 hours for the great majority of the combinations studied, except against the two strains highly resistant to gentamicin. Combination of every beta-lactam at 1/2 MIC with gentamicin was synergistic (except in case of high level resistance to gentamicin) and prevented bacterial growth but was not bactericidal. Against two strains of E. faecium with high MICs of amoxicillin (8 mg/l), piperacillin-tazobactam (64 mg/l) and ticarcillin-clavulanic acid (512 mg/l), only combinations of amoxicillin 100 mg/l and gentamicin were always bactericidal. In conclusion, against E. faecalis strains, ticarcillin-clavulanic acid tested at 100 micrograms/ml had a bactericidal activity similar to that of the other beta-lactams tested, alone or combined with gentamicin.(ABSTRACT TRUNCATED AT 250 WORDS)
Leclercq
R
R
Service de Bactériologie-Virologie-Hygiène, Hôpital Henri-Mondor, Créteil, France.
Duval
J
J
D000658:Amoxicillin / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D019818:Clavulanic Acid; D002969:Clavulanic Acids / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D004359:Drug Therapy, Combination / Q000494:pharmacology; D013293:Enterococcus faecalis / Q000187:drug effects*; D016984:Enterococcus faecium / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005839:Gentamicins / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D010403:Penicillin Resistance; D010878:Piperacillin / Q000494:pharmacology; D000078142:Tazobactam; D013982:Ticarcillin / Q000494:pharmacology*; D065093:beta-Lactamase Inhibitors
D000900:Anti-Bacterial Agents; D002969:Clavulanic Acids; D004791:Enzyme Inhibitors; D005839:Gentamicins; D065093:beta-Lactamase Inhibitors; D019818:Clavulanic Acid; D000658:Amoxicillin; D010397:Penicillanic Acid; D013982:Ticarcillin; D000078142:Tazobactam; D010878:Piperacillin
Activité bactéricide des associations de ticarcilline-acide clavulanique ou d'autres beta-lactamines (amoxicilline, pipéracilline-tazobactam, ticarcilline) avec la gentamicine vis-à-vis des Enterococcus faecalis et E. faecium.