virginiamycin virginiamycin virginiamycin is a streptogramin antibiotic similar to pristinamycin and quinupristin/dalfopristin. it is a combination of pristinamycin iia (virginiamycin m1) and virginiamycin s1. virginiamycin is used in the fuel ethanol industry to prevent microbial contamination. it is also used in agriculture, specifically in livestock, to accelerate the growth of the animals and to prevent and treat infections. antibiotics also save as much as 30% in feed costs among young swine, although the savings fade as pigs get older, according to a usda study. virginiamycincombination ofvirginiamycin s1streptogramin b antibioticpristinamycin iiastreptogramin a antibioticclinical dataahfs/drugs.comfda professional drug informationmedlineplusa603007atc coded06ax10 (who) qj01fg90 (who)identifierscas number11006-76-1 ydrugbankdb01669 nuniic49ws9n75lkeggd06311 ychebichebi:87209 nniaid chemdb008734e numbere711 (antibiotics) comptox dashboard (epa)dtxsid30873800 echa infocard100.031.119 chemical and physical datamelting point138 to 140 °c (280 to 284 °f) (dec.) ny (what is this?) (verify)