Title: Comparative bactericidal effect of ceforanide (BL-S 786) and five other cephalosporins in an in vitro pharmacokinetic model.
Abstract: The bactericidal activity of ceforanide was compared, in an in vitro kinetic model, with thatof five other cephalosporins: cephalothin, cefazolin, cefamandole, cefuroxime, and cefoxitin.Cultures of various pathogens in 95% human serum were incubated for 12 hours in the presenceof the cephalosporins whose concentrations were modified periodically-by addition of aconcentrated solution of drug or dilution with unmedicated serum-in order to simulate thevariation of antibiotic concentration in human blood after a one-gram intramuscular dose.One Gram-positive strain and six Gram-negative strains were used. Bactericidal activitywas assessed by monitoring changes in the number of colony-forming units.Tests showed that against Klebsiella pneumoniae, ceforanide was the most active of thesix cephalosporins. Proteus mirabilis was more susceptible to ceforanide and cefuroximethan to the other compounds; Enterobacter cloacae to ceforanide, cefuroxime, and cefamandole;Escherichia coli to ceforanide, cefuroxime, cefamandole, and cefazolin. The number ofviable cells of Staphylococcus aureus was reduced below detectable levels by all cephalosporinsexcept cefoxitin. On the other hand, Providencia stuartii was virtually unaffected by all ofthe cephalosporins except cefoxitin.