Mersacidin, a new antibiotic from Bacillus. Fermentation, isolation, purification and chemical characterization.

Mersacidin (1) is a new peptide antibiotic containing beta-methyllanthionine. It is classified as a member of the proposed lantibiotic group of antibiotics, and is produced by a species of Bacillus. Mersacidin has a molecular weight of 1,824 (C80H120N20O21S4). The antibiotic is active against Gram-positive organisms including methicillin-resistant Staphylococcus aureus, but has no activity against Gram-negative bacteria or fungi.