The streptogramin antibiotics: update on their mechanism of action

Abstract
Antibiotics of the streptogramin class are an association of two types of chemically different compounds, group A molecules and group B molecules, acting in synergy. The combination of these molecules generally inhibits bacterial growth at a lower concentration than does either the group A or group B molecule alone and is often bactericidal against strains of bacteria for which each type of molecule alone is only bacteriostatic. The semisynthetic streptogramin quinupristin/dalfopristin (RP 59500), the first water-soluble member of this class, is under development for the treatment of severe infections caused by methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, penicillin-resistant Streptococcus pneumoniae, glycopeptide-resistant Enterococcus faecium, and other organisms. The streptogramins block the translation of mRNA into protein. Both group A and group B molecules bind to the peptidyl-transferase domain of the bacterial ribosome. The group B molecule stimula...