Olivanic acids, a family of .BETA.-lactam antibiotics with .BETA.-lactamase inhibitory properties produced by Streptomyces species. I. Detection, properties and fermentation studies.

The screening of soil actinomyces for beta-lactamase inhibitors is described. Using a plate test a number of strains of Streptomyces were found to produce beta-lactamase inhibitory activity designated olivanic acid complex. Factors affecting the production of this complex by Streptomyces olivaceus ATCC 21379 are reported. The complex showed antibacterial activity and also inhibited a number of different types of beta-lactamase in a progressive manner. Certain ampicillin-resistant bacteria are rendered sensitive to ampicillin in the presence of olivanic acid complex at a concentration which alone did not inhibit growth.