Serum bactericidal activity of ampicillin and mezlocillin with and without sulbactam

Two groups of five volunteers received the following regimens on three consecutive days: group 1: ampicilllin 3 g, sulbactam 1 g, ampicillin 3 g + sulbactam 1 g; group 2: mezlocillin 3 g, sulbactam 1 g, mezlocillin 3 g + sulbactam 1 g. The drugs were given intravenously. Serum bactericidal activity (SBA) was measured against 24 strains producing various beta-lactamases: 3 Staphyloccus aureus, 3 Escherichia coli, 4 Klebsiella pneumoniae, 2 indole-positive Proteus, 4 Pseudomonas aeruginosa, 2 Bacteroides fragilis and 3 Bacteroides thetaiotaomicron. One strain of penicillin-sensitive Staphylococcus aureus was also tested. Sulbactam significantly increased the SBA of ampicillin against S. aureus, B. fragilis and B. thetaiotaomicron. Sulbactam increased the SBA of mezlocillin against S. aureus only.SCOPUS: NotDefined.j