Drugs & Medication

The rifamycins are a group of antibiotics which are synthesized either naturally by the bacterium Amycolatopsis mediterranei, or artificially. Rifamycins are particularly effective against mycobacteria, and are therefore used to treat tuberculosis, leprosy, and mycobacterium avium complex (MAC) infections.

The rifamycin group includes the "classic" rifamycin drugs as well as the rifamycin derivatives Rifampicin, Rifabutin and Rifapentine.

Contents 1 The bacterium 2 The classic rifamycin drugs 3 The rifamycin derivatives 4 Currently available rifamycins 5 References 6 External links

The bacterium

Streptomyces mediterranei was first isolated in 1957 from a soil sample collected near the beachside town of St Raphael in southern France. The name was originally given by two microbiologists working with the Italian drug company Group Lepetit SpA in Milan, the Italian Grazia Beretta and Pinhas Margalith of Israel.

In 1969 the bacterium was renamed Nocardia mediterranei when another scientist named Thiemann found that it had a cell wall typical of the Nocardia species. Then in 1986 the bacterium was renamed again as Amycolatopsis mediterranei, as the first species of a new genus, because a scientist named Lechevalier discovered that the cell wall lacked mycolic acid and was not able to be infected by the Nocardia and Rhodococcus phages.

The classic rifamycin drugs

Rifamycins were first isolated in 1957 from a fermentation culture of Streptomyces mediterranei at the laboratory of Gruppo Lepetit SpA in Milan by a scientist named Piero Sensi, working with the Israeli scientist Pinhas Margalith. Eventually around seven rifamycins were discovered, named Rifamycin A, B, C, D, E, S and SV.

Of the various rifamycins Rifamycin B was first introduced commercially. Lepetit filed for patent protection of Rifamycin B in the UK in August 1958 and in the US in March 1959. The British patent GB921045 was granted in March 1963 and U.S. Patent 3,150,046 was granted in September 1964. The drug is widely regarded as having helped conquer the issue of drug-resistant tuberculosis in the 1960s.

The rifamycin derivatives

Lepetit introduced Rifampicin, an orally active rifamycin, around 1966. Rifabutin, a derivative of rifamycin S, was invented around 1975 and came on to the US market in 1993. Hoechst Marion Roussel (now part of Aventis) introduced rifapentine in 1999.

Rifaximin is a oral rifamycin marketed in the US by Salix Pharmaceuticals that is not absorbed from the intestine. It is intended to treat intestinal infections due to Escherichia coli.

Currently available rifamycins

• Rifampicin
  Rifabutin
  Rifapentine
  Rifaximin

References

• Sensi. et al., Farmaco Ed. Sci. (1959) 14, 146-147 - the paper announcing the discovery of the rifamycins.
• Thieman et al. Arch. Microbiol. (1969), 67 147-151 - the paper which renamed Streptomyces mediterranei as Nocardia mediterranei.
• Lechevalier et al., Int. J. Syst. Bacteriol. (1986), 36, 29) - the paper which renamed Nocardia mediterranei as Amycolatopsis mediterranei.

External links

• U.S. Patent 3,150,046 for Rifamycin B.