Snapshot A 52-year-old man presents to the emergency room 2 weeks after surgical repair of a burst appendicitis. His post-operative course was uncomplicated and he was sent home 2 days after his surgery. Over the past week, he reports feeling increased abdominal pain, low-grade fevers, and fatigue. On physical exam, his abdomen is tender to palpation. An abdominal CT scan shows an abscess in the right lower quadrant. Blood cultures are taken and he is started on empiric antibiotics. Two days later, blood cultures reveal vancomycin-resistant Enterococcus faecium. Sensitivities demonstrated that the bacteria is sensitive to linezolid and streptogramins, but resistant to daptomycin. Due to an allergy to linezolid, he is started on a combination of 2 streptogramins that act synergistically. Introduction Drugs quinupristin dalfopristin quinupristin and dalfopristin are often used together synergistically Mechanism of action inhibits protein synthesis by acting on the 50S subunit of the ribosome dalfopristin inhibits the early phase of protein synthesis quinupristin inhibits the late phase bacteriostatic against enterococci bactericidal against staphylococci Clinical use treatment of highly resistant bacteria vancomycin-resistant Enterococcus faecium (VRE) skin and soft tissue infection methicillin-resistant staphylococci (MRSA) Adverse effects injection site irritation and edema gastrointestinal upset thrombophlebitis