Antimicrobial
Streptogramins
Synergistic 50S protein-synthesis blockers
strep-toh-GRAM-inz
High-yield clue
The two streptogramin components are synergistic: dalfopristin binding reshapes the ribosome to boost quinupristin binding, turning bacteriostatic into bactericidal.
Overview
An antibacterial class (quinupristin-dalfopristin) of two components that bind the 50S ribosomal subunit at adjacent sites, used to teach synergistic ribosome inhibition of resistant Gram-positives.
Classification
- Antibacterial
- 50S ribosomal subunit target
- Two-component (A + B) synergy
- Gram-positive spectrum vocabulary
Lab & identification clues
- Bind peptidyl transferase center / exit tunnel vocabulary
- Quinupristin binds like a macrolide in the exit tunnel concept
- Cross-resistance with macrolides/lincosamides (MLS) framing
Associations
- Resistant Gram-positive study association (vancomycin-resistant E. faecium and MRSA; E. faecalis is intrinsically resistant)
- Protein synthesis inhibition concept
- MLSb resistance vocabulary
Commonly confused with
- Macrolides
- Lincosamides (clindamycin)
Your notes
Original mechanism summary for microbiology study. Sources checked: CDC antimicrobial-resistance guidance, NCBI Bookshelf Medical Microbiology, and standard coursework frameworks; reviewed 2026-06. Covers class, mechanism, and resistance vocabulary only; no prescribing, dosing, or patient-specific treatment guidance.