virginiamycin Virginiamycin: A cyclic polypeptide antibiotic complex from Streptomyces virginiae, S. loidensis, S. mitakaensis, S. pristina-spiralis, S. ostreogriseus, and others. It consists of 2 major components, VIRGINIAMYCIN FACTOR M1 and virginiamycin Factor S1. It is used to treat infections with gram-positive organisms and as a growth promoter in cattle, swine, and poultry.. virginiamycin : A mixture of cyclic polypeptide streptogramin antibiotics produced by Streptomyces virginiae, S. loidensis, S. mitakaensis, S. pristina-spiralis, S. ostreogriseus, and others. The two major components are virginiamycin M1 (also known as pristinamycin IIA) and virginiamycin S1. Virginiamycin has been widely used as a growth promotion agent in livestock and has been to have bacteriostatic activity against Gram-positive organisms such as staphylococci and streptococci. | 2.89 | 4 | 0 | | |