rifamycin

[rĭf′ə-mīsĭn]
n.
  1. Any of a group of antibiotics originally isolated from a strain of the soil microorganism Streptomyces mediterranei, used in the treatment of leprosy, tuberculosis, and other bacterial diseases.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.