dalfopristin

Description: Dalfopristin is a semi-synthetic streptogramin antibiotic analogue of ostreogyrcin A (virginiamycin M, pristinamycin IIA, streptogramin A). Quinupristin/Dalfopristin (Q/D) is a valuable alternative antibiotic to vancomycin for the treatment of multi-drug resistant Enterococcus faecium infections. The combination quinupristin/dalfopristin (marketed under the trade name Synercid) was brought to the market by Rhone-Poulenc Rorer Pharmaceuticals in 1999. Synercid (weight-to-weight ratio of 30% quinupristin to 70% dalfopristin) is used to treat infections by staphylococci and by vancomycin-resistant Enterococcus faecium. Both dalfopristin and quinupristin bind to sites located on the 50S subunit of the ribosome. Initial dalfopristin binding results in a conformational change of the ribosome, allowing for increased binding by quinupristin. A stable drug-ribosome complex is created when the two drugs are used together. This complex inhibits protein synthesis through prevention of peptide-chain formation and blocking the extrusion of newly formed peptide chains. In many cases, this leads to bacterial cell death.

References: Tex Heart Inst J. 2010; 37(4):400-4; BMC Microbiol. 2016 Oct 21; 16(1):246.