Pyostacine
Virginiamycin is a class of streptogramin-related depsipeptides isolated from the bacterium Streptomyces virginiae and other Streptomyces bacterial species.  The virginiamycins consist of two major components, virginiamycin M1 and virginiamycin S1.  These agents bind to and inhibit ribosome assembly, thereby preventing protein synthesis.  Active against Gram-positive bacteria, these antibiotics are primarily used in veterinary practice. (NCI04)