Rifabutin

Rifabutin (Rfb) is a bactericidal antibiotic drug primarily used in the treatment of tuberculosis. The drug is a semi-synthetic derivative of rifamycin S. Its effect is based on blocking the DNA-dependent RNA-polymerase of the bacteria. It is effective against Gram-positive and some Gram-negative bacteria, but also against the highly resistant mycobacteria, e.g. Mycobacterium tuberculosis, M. leprae, and M. avium intracellulare.