Fidaxomicin is a macrocyclic antibiotic, isolated from actinomycete Dactylosporangium aurantiacum. Fidaxomicin is an RNA polymerase inhibitor that has a narrow antibiotic activity spectrum and is not readily absorbed into the blood circulatory system.This anti-bacterial agentis almost Clostridium difficile specific in the colon, and has minimal effect to the intestinal microbial flora.; Purity: 98%; Molecular Weight: 1058.05, 25 mg