Tiacumicins, a novel complex of 18-membered macrolide antibiotics. I. Taxonomy, fermentation and antibacterial activity.

A complex of 18-membered macrolide antibiotics has been discovered in the fermentation broth of strain AB718C-41. The producing culture, isolated from a soil sample collected in Hamden, Connecticut, was identified as a strain of Dactylosporangium aurantiacum and was designated D. aurantiacum subsp. hamdenesis subsp. nov. The antibiotic complex was produced in a New Brunswick 150-liter fermentor using a medium consisting of glucose, soybean oil, soybean flour, beef extract and inorganic salts. Several of the antibiotics were active against sensitive and multiple antibiotic-resistant strains of pathogenic Gram-positive bacteria.