Quinupristin and Dalfopristin belongs to which of the following class of drug:

Quinpristin and Dalfopristin is a combination of Streptogramins. Rapidly Bactericidal for most susceptible organisms except Enterococcus faecium, which is killed slowly. Quinpristin is Streptogramin B while Dalfopristin is Streptogramin A. They bind to 50S Ribosomal RNA and inhibit protein synthesis . They are active against - Gram positive cocci, including Multidrug resistant strains of Streptococci, Penicillin resistant strains of S. pneumoniae, Methicillin susceptible and resistant strains of Staphylococci, and E.faecium (but not Enterococcus faecalis). Resistance is due to modification of the Quinupristin binding site (MLS-B type resistance), enzymatic inactivation of Dalfopristin or efflux.