Rifamycins are antibiotics that inhibit DNA-dependent RNA polymerases and are usually bactericidal against Gram-positive bacteria but bacteriostatic against Gram-negative bacteria. Rifamycins are also effective against Mycobacterium species, including M. tuberculosis. Rifabutin is a broad-spectrum rifamycin antibiotic that has applications against tuberculosis, H. pylori, M. avium complex, Chlamydia, and other bacteria. It is also useful in co-infections with human immunodeficiency virus, including tuberculosis.
