Rifamycin
Rifamycin is a natural antibiotic produced by Streptomyces mediterranei, Rifamycin (Ansamycin Family) is a commonly used antimycobacterial drug that inhibits prokaryotic DNA-dependent RNA synthesis and protein synthesis; it blocks RNA-polymerase transcription initiation. Rifamycin has an activity spectrum against Gram-positive and Gram-negative bacteria, but is mainly used against Mycobacterium sp. (especially M. tuberculosis) in association with other agents to overcome resistance. (NCI04)