beta-Lactamase inhibition and in vitro activity of sulbactam and sulbactam/cefoperazone.

beta-Lactamase inhibitors such as sulbactam are beta-lactam compounds that have low antimicrobial activity but are able to inhibit enzymes (beta-lactamases) that destroy beta-lactam antibiotics like penicillins and cephalosporins. The main activity of beta-lactamase inhibitors is directed against plasmid-mediated transferable enzymes and various extended-spectrum enzymes. Sulbactam is also active against some of the fixed chromosomally mediated enzymes produced by gram-negative bacteria and is active against Bacteroides and Acinetobacter species. Cefoperazone, a third-generation cephalosporin, is active against a wide range of gram-positive and gram-negative bacteria, including Enterobacteriaceae and Pseudomonas species. However, transferable beta-lactamases are now produced by numerous gram-negative organisms, mitigating the effectiveness of therapy with this agent. Chromosomally mediated enzymes are less common but can be induced in some strains of Klebsiella, Enterobacter, and Serratia species. The full potential of cefoperazone against Enterobacteriaceae and Pseudomonas species is restored by the addition of sulbactam; this addition extends cefoperazone's spectrum of activity to include Bacteroides and Acinetobacter species.