Streptomyces mediterranei

Rifamycins. The rifamycins were first isolated from a broth of Nocardia mediterranei (the producing organism was originally identified as Streptomyces mediterranei). The rifamycins, the stmctures of which are shown in Figure 3, were originally designated as rifomycins. Only rifamycin B (22), which accounts for 10—15% of the cmde complex, can be isolated easily as a stable, crystalline compound (6,89,90). 

Rifamycin Streptomyces mediterranei Tuberculosis Protein synthesis... 

Rifampin is a semisynthetic macrocyclic antibiotic produced from Streptomyces mediterranei. It is a large lipid-soluble molecule that is bactericidal for both intracellular and extracellular microorganisms. Rifampin binds strongly to the p-subunit of bacterial DNA-dependent RNA polymerase and thereby inhibits RNA synthesis. Rifampin does not affect mammalian polymerases. 

The rifamycins, a class of antibacterials isolated from Streptomyces mediterranei, contain a macrocyclic ring bridging across two nonadjacent positions on an aromatic system. Rifampicin (9.96), a semisynthetic derivative of rifamycin, is a drug of choice in the treatment of tuberculosis as well as leprosy, either alone or in combination with other drugs. Rifampicin is much safer than other antituberculotics since it inhibits DNA-directed RNA polymerase in bacteria but not in mammals. Another rifamycin, rifabutin (9.97), is a spiroimidazopiperidyl derivative of the rifamycin. 

Rifampin is a semisynthetic derivative of rifamycin, an antibiotic produced by Streptomyces mediterranei. It is active in vitro against gram-positive and gram-negative cocci, some enteric bacteria, mycobacteria, and chlamydia. Susceptible organisms are inhibited by less than 1 mcg/mL. Resistant mutants are present in all microbial populations at... 

The rifamycins are ansamycin antibiotics produced by cultures of Amycolatopsis mediterranei (formerly Nocardia mediterranei or Streptomyces mediterranei). The crude antibiotic mixture was found to contain five closely related substances rifamycins A-E, but if the organism was cultured in the presence of sodium diethyl barbiturate (barbitone or barbital), the product was almost entirely rifamycin B (Figure 3.71). Rifamycin B has essentially no antibacterial activity, but on standing in aqueous solution in the presence of air, it is readily transformed by oxidation and intramolecular nucleophilic addition into rifamycin O, which... 

Rifamycin SV is a semi-synthetic antibiotic derived from rifamycin B, a substance produced during growth of certain strains of Streptomyces mediterranei. 

The rifamycins are a group of macrocyclic antibiotics that were originally derived from a culture of Streptomyces mediterranei, the products of which were named after the French film Rififi chez les hommes (director Jules Dassin). 

Rifampin is used as an antibiotic. It is a semisynthetic derivative of rifamycin B, a macrocyclic antibiotic produced by the mold Streptomyces mediterranei. 

Rifampicin (Fig. 10.70) is a semisynthetic rifamycin made from rifamycin B—an antibiotic isolated from Streptomyces mediterranei. It inhibits Gram-positive bacteria and works by binding non-covalently to RNA polymerase and inhibiting RNA synthesis. The DNA-dependent RNA polymerases in eukaryotic cells are unaffected, since the drug binds to a peptide chain not present in the mammalian RNA polymerase. It is therefore highly selective. 

Rifampicin-a semisynthetic derivative of naphthalene was produced by Streptomyces mediterranei. 

The rifamycins are members of the ansamycin class of natural products produced by Streptomyces mediterranei. This chemical class is characterized as molecules with an... 

Rifamycins are microbial-derived macrolides that were isolated in 1957 from the actinomycete Streptomyces mediterranei, obtained from the soil of the pine forests of southern France [18]. Of these, rifamycin B (306) is the least toxic. Addition of diethylbarbituric acid to the fermentation medium results in the production of 306 only. Rifampicin is the C3-hydazone semisynthetic derivative of rifamycins. Rifamycins show in vitro and in vivo anti-poxyviruses, e.g., VV activities [18]. These activities are apparently due to inhibition of the early step of viral morphogenesis which affects the assembly of immature viral particles. The inhibitory activity of rifamycins on retroviruses is also reported [18]. Many natural and semisynthetic rifamycins inhibit the virion RNA-dependent DNA polymerase (RT) [18]. Rifamycin B (306) was reported active against murine sarcoma virus (MSV) due to its RT, focus formation and cell transformation inhibitory activities [18]. Rifamycin antibiotics also inhibit the RT of Rauuscher leukemia virus, preventing its leukomogenic activity [18]. 

The biogenetic relationships of rifamycin S (2) and related compounds were discussed by Lancini et al. (1969). According to this research, incubation of 2 with the washed mycelium of Streptomyces mediterranei gives rifamycin B (1). The hypothesis that rifamycin O (7) was a progenitor in the biosynthesis of rifamycin B (1) was excluded because 2 (and/or 3) was transformed into 1. In addition, it was found that 1 and 7 are formed from 2 (and/or 3) by different pathways using different C3-precursors for the biosynthesis of their glycolic acid moieties [45,194]. 

The rifamycins are antibiotics isolated in Italy from Streptomyces mediterranei and then chemically altered to give more selective products. Rifamycin SV 4.37a) is the original substance but its derivative rifampicin (rifampin in the USA) 4.37b) is now the established drug in this series. It is much used, in conjunction with isoniazid (Section 11.9), for the cure of severe cases of tuberculosis but is still too expensive for general use (American Thoracic Society, 1980). Because it is one of the most selective of all known anti-bacterial drugs, it could profitably... 

Rifamycins belong to a group of antibiotics some of which are biosynthesized in fermentation cultures by the bacterium Amycolatopsis rifamyci-nica while some are sanisynthelic compounds prepared by derivitization. The name of the bacterium that produces rifamycins has evolved from the original Streptomyces mediterranei to Nocardia mediterranei, then to Amycolatopsis mediterranei, and in 2004 to A. rifamycinica. 

Rifamycin Antibiotics - Derived from the fermentation of Streptomyces mediterranei, this family of ansa-macrollde drugs possesses a very broad spectrum of antimicrobial activity against gram-positive and gram-negatire bacteria, mycobacteria, chlamydia, and several viruses. The activity of rifampin, the only clinical candidate of this group, has recently been reviewed by Lester.35 its efficacy is presumably due to the inhibition of bacterial derived DNA-dependent RNA polymerase and the inhibition of viral RNA-dependent DNA polymerase (reverse transcriptase). 

Rifampicin (RIF, Fig. 22.50) is a broad-spectmm semisynthetic derivative of the complex macrocyclic antibiotic rifamycin B, produced by Streptomyces mediterranei, and is known as rifampin outside the UK. An important feature about RIF is that it is active against both actively growing and slowly metabolising non-growing bacilli. The latter feature is thought to be important in reducing the treatment from 12-18 months to 9 months. 

Substances that inhibit the synthesis of RNA. The rifamycins are antibiotics isolated in Italy from Streptomyces mediterranei and then chemically altered in the laboratory to give more useful products. Of these, rifamycin SV (4.20a) provided early clinical experience, but rifampin (rifampicin) (4.20b) has become the standard medication. Among the most selective of all known drugs, the rifamycins are used early in tuberculosis, and also for curing drug-resistant tuberculosis also for resistant staphylococcal infections. Were they less expensive, they would be used a great deal more. 

Thiemann, J. E., G. Zucco, and G. Pelizza A Proposal for the Transfer of Streptomyces mediterranei Margalith and Beretta 1960 to the Genus Nocardia as Nocardia mediterranei (Margalith and Beretta) Comb. Nov. Arch. Mikrobiol. 67, 147 (1969). 

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