Rifabutin (Synonyms: Ansamycin, LM-427)

Rifabutin is a naphthalenic ansamycin that derives from rifamycin S and has the activity to against mycobacteria infection with MICs ranged from 0.125 to 0.25 µg/ml [1].
TB (tuberculosis) is a chronic infectious disease caused by Mycobacterium tuberculosis infection. TB can invade to human organs whole body, but mainly affects the lung which is called pulmonary tuberculosis. About 2 billion people has been infected with TB all around the word and the emergence of new infected TB patients is about 8-10 million every year. Rifabutin is an anti-TB medicine used to treat TB infected patients with fewer side effects [1].
Rifabutin is a potent antimycobacterial medicine and has lower toxic than rifampicin. When tested with the mimic human-bacterial plasma membranes, Rifabutin showed high affinity for the bacterial membrane mediated by electrostatic interactions with the phospholipid head groups [2]. In patients with organ transplant, Rifabutin was an excellent medicine to reduce the incidence of TB (tuberculosis) infection [3]. When tested 34 isolates of clinical drug resistant M.tuberculosis with Rifabutin, they showed sensitive to Rifabutin compared with rifampicin treatment [1].
In mice model with TB infected, intravenous administration of Rifabutin reduced bacterial loads in spleen, liver and lung [4].
References:
[1].    Pham, D.D., E. Fattal, and N. Tsapis, Pulmonary drug delivery systems for tuberculosis treatment. Int J Pharm, 2014. 478(2): p. 517-529.
[2].    Pinheiro, M., et al., Differential interactions of rifabutin with human and bacterial membranes: implication for its therapeutic and toxic effects. J Med Chem, 2013. 56(2): p. 417-26.
[3].    Tabarsi, P., et al., Mycobacterial infection and the impact of rifabutin treatment in organ transplant recipients: A single-center study. Saudi J Kidney Dis Transpl, 2015. 26(1): p. 6-11.
[4].    Gaspar, M.M., et al., Rifabutin encapsulated in liposomes exhibits increased therapeutic activity in a model of disseminated tuberculosis. Int J Antimicrob Agents, 2008. 31(1): p. 37-45.