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🦠microbiology review

Streptogramins

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Streptogramins are a class of antibacterial drugs that inhibit bacterial protein synthesis by targeting the 50S subunit of the bacterial ribosome. They are effective against a wide range of Gram-positive bacteria, including those that are resistant to other antibiotics.

5 Must Know Facts For Your Next Test

  1. Streptogramins are a combination of two structurally distinct compounds, type A and type B, that work synergistically to inhibit bacterial protein synthesis.
  2. The type A component binds to the peptidyl transferase center of the 50S ribosomal subunit, preventing the formation of the peptide bond, while the type B component binds to a different site on the 50S subunit, disrupting the elongation of the polypeptide chain.
  3. Streptogramins are effective against a wide range of Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE).
  4. The use of streptogramins is often reserved for the treatment of infections caused by multidrug-resistant Gram-positive bacteria, as they can overcome certain resistance mechanisms that render other antibiotics ineffective.
  5. Streptogramins have a low potential for the development of resistance due to their unique mechanism of action and the synergistic effect of the type A and type B components.

Review Questions

  • Describe the mechanism of action of streptogramins and explain how the two components (type A and type B) work synergistically to inhibit bacterial protein synthesis.
    • Streptogramins are a combination of two structurally distinct compounds, type A and type B, that work together to inhibit bacterial protein synthesis. The type A component binds to the peptidyl transferase center of the 50S ribosomal subunit, preventing the formation of the peptide bond. The type B component binds to a different site on the 50S subunit, disrupting the elongation of the polypeptide chain. This synergistic mechanism of action makes streptogramins effective against a wide range of Gram-positive bacteria, including those that are resistant to other antibiotics.
  • Discuss the clinical significance of streptogramins in the treatment of bacterial infections, particularly in the context of multidrug-resistant pathogens.
    • Streptogramins are often used to treat infections caused by multidrug-resistant Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). Their unique mechanism of action, which involves the synergistic effects of the type A and type B components, allows them to overcome certain resistance mechanisms that render other antibiotics ineffective. The low potential for the development of resistance further enhances the clinical utility of streptogramins in the management of challenging bacterial infections.
  • Analyze the role of streptogramins in the broader context of antibiotic resistance and the need for novel antimicrobial strategies.
    • The emergence of multidrug-resistant bacteria has become a significant public health concern, underscoring the need for innovative antimicrobial strategies. Streptogramins, with their unique mechanism of action and low potential for resistance development, play a crucial role in addressing this challenge. By targeting bacterial protein synthesis through the synergistic effects of their type A and type B components, streptogramins offer a valuable treatment option for infections caused by resistant Gram-positive pathogens. The continued research and development of streptogramins and other novel antibacterial agents are essential to combat the growing threat of antimicrobial resistance and ensure the availability of effective treatment options for patients.