Pristinamycin (INN), also spelled pristinamycine, is an antibiotic used primarily in the treatment of staphylococcal infections, and to a lesser extent streptococcal infections. It is a streptogramin group antibiotic, similar to virginiamycin, derived from the bacterium Streptomyces pristinaespiralis. It is marketed in Europe by Sanofi-Aventis under the trade name Pyostacine.
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| Pristinamycin IA | antibiotic |
| Pristinamycin IIA | antibiotic |
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| AHFS/Drugs.com | International Drug Names |
| MedlinePlus | a603007 |
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Pristinamycin is a mixture of two components that have a synergistic antibacterial action. Pristinamycin IIA is a macrolide , and results in pristinamycin's having a similar spectrum of action to erythromycin. Pristinamycin IA (streptogramin B) is a depsipeptide.[1] PI and PII are coproduced by S. pristinaespiralis in a ratio of 30:70. Each compound binds to the bacterial 50 S ribosomal subunit and inhibits the elongation process of the protein synthesis, thereby exhibiting only a moderate bacteriostatic activity. However, the combination of both substances acts synergistically and leads to a potent bactericidal activity that can reach up to 100 times that of the separate components.
The pristinamycin biosynthetic gene cluster is the largest antibiotic supercluster known so far, with a size of ~210 kb, wherein the PI and PII biosynthetic genes are not clustered individually but are scattered across the complete sequence region.[2] Furthermore, this biosynthetic gene region is interrupted by a cryptic type II PKS gene cluster.
Clinical use
Despite the macrolide component, it is effective against erythromycin-resistant staphylococci and streptococci.[3][4] It is active against methicillin-resistant Staphylococcus aureus (MRSA). Its usefulness for severe infections, however, may be limited by the lack of an intravenous formulation owing to its poor solubility.[5] Nevertheless, it is sometimes used as an alternative to rifampicin+fusidic acid or linezolid for the treatment of MRSA.
The lack of an intravenous formulation led to the development of the pristinamycin-derivative quinupristin/dalfopristin (i.e., Synercid), which may be administered intravenously for more severe MRSA infections.