Serum bactericidal activity after administration of four cephalosporins in healthy volunteers.

Serum bactericidal activity (SBA) was determined against ten strains each of Staphylococcus aureus, Klebsiella pneumoniae, Proteus vulgaris and Enterobacter cloacae in six volunteers 1 h and 4 h after intravenous infusion of 1 g and 2 g cefotaxime and cefmenoxime, and 2 g flomoxef, and against ten strains of Pseudomonas aeruginosa after infusion of 1 g and 2 g ceftazidime. Flomoxef showed the highest SBA against methicillin-susceptible Staphylococcus aureus. All cephalosporins had high SBA against gram-negative rods. Cefotaxime had the highest SBA against Klebsiella pneumoniae and Enterobacter cloacae. The SBA against Pseudomonas aeruginosa after 1 g and 2 g doses of ceftazidime was very similar.