title: In vivo significance of the inoculum effect of antibiotics on Escherichia coli.
abstract: The minimum dosage of antibiotics which reduced mortality in rats intraperitoneally inoculated with an Escherichia coli isolate was determined. Low mortality rates (0-10%) were obtained when antibiotics with minimal or no inoculum effect (cefoxitin, cefmetazole and gentamicin) were administered to yield serum levels 3 to 20 times the MIC, while antibiotics with a pronounced inoculum effect (cefotaxime and aztreonam) had to be administered to yield serum levels 200 to 1,000 times the MIC determined with a standard (low) inoculum. Thus, it seems that the inoculum effect observed in vitro with some antibiotics for Escherichia coli may have clinical significance.
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001398:Aztreonam / Q000008:administration & dosage / Q000627:therapeutic use; D015311:Cefmetazole; D002439:Cefotaxime / Q000008:administration & dosage / Q000627:therapeutic use; D002440:Cefoxitin / Q000008:administration & dosage / Q000627:therapeutic use; D002513:Cephamycins / Q000008:administration & dosage / Q000627:therapeutic use; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects*; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000382:microbiology; D005260:Female; D005839:Gentamicins / Q000008:administration & dosage / Q000627:therapeutic use; D008826:Microbial Sensitivity Tests; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000900:Anti-Bacterial Agents; D002513:Cephamycins; D005839:Gentamicins; D015311:Cefmetazole; D002440:Cefoxitin; D001398:Aztreonam; D002439:Cefotaxime