Four further antibiotics related to olivanic acid produced by Streptomyces olivaceus: fermentation, isolation, characterisation and biosynthetic studies.

Four beta-lactam antibiotics with beta-lactamase inhibitory activity MM 22380, MM 22381, MM 22382 and MM 22383 containing the carbapenem nucleus have been isolated from a culture of Streptomyces olivaceus ATCC 31365. Fermentation conditions for their production and methods for their isolation are described. Evidence for a biosynthetic link between these compounds and the previously described olivanic acid derivatives MM 4550, MM 13902 and MM 17880 is presented.