Streptogramins

"Synercid" - quinupristrin-dalfoprisin

Use

• treating vancomycin resistant Enterococcus faecium infections

Properties

• cyclic peptides

• combination of streptogramin A and streptogramin B that act synergistically

Mechanism

• dalfopristin binds 50S subunit - induces conformational change that facilitates binding of quinupristin

• dalfropristin prevents peptide elongation

• quinupristin intiates premature release of peptide chains

Activity

• staphylococci

• streptococci

• Enterococcus faecium (not E. faecalis)