Development of beta-lactamase inhibitors.

The resistance of bacteria to beta-lactam antibiotics was first associated with the production of the enzyme beta-lactamase as long ago as 1940. Since then, increasing numbers of beta-lactamase-producing bacteria capable of inactivating penicillins and cephalosporins have been isolated clinically. One approach to the problem posed by beta-lactamase-producing bacteria has been to seek substances that function as inhibitors of beta-lactamase and that can be used to protect beta-lactam antibiotics from destruction by the bacterial enzymes. The first clinically available inhibitor was clavulanic acid, a metabolite of Streptomyces clavuligerus that was identified in a screening program for naturally occurring beta-lactamase inhibitors. Clavulanic acid is a potent inhibitor of many bacterial beta-lactamases and has been formulated with amoxicillin and ticarcillin to produce broad-spectrum antibiotic combinations active against beta-lactamase-producing bacteria. After the discovery of clavulanic acid, various compounds have been reported to function as inhibitors of bacterial beta-lactamases, but only sulbactam and its prodrug, sultamicillin, have become available commercially. The success of clavulanic acid has confirmed beta-lactamase inhibitors as one solution to the problem of antibiotic-resistant bacteria.