Lecture Notes: Vancomycin

Introduction

• Vancomycin: Antibiotic named from the word "vanquish."
• Developed to treat methicillin-resistant organisms.

Historical Context

• Penicillin: Initially used widely, but bacteria developed resistance through beta-lactamases.
• Methicillin: Introduced to overcome penicillin resistance, led to methicillin-resistant Staphylococcus aureus (MRSA).
• Vancomycin: Initially considered the last line of defense against MRSA.
  • Not the only line of defense anymore, but was a significant development in antibiotic treatment.

Mechanism of Action

• Type: Glycoprotein antibiotic.
• Function: Inhibits cell wall synthesis.
  • Blocks proteins from being incorporated into the bacterial cell wall.
• Spectrum: Narrow spectrum antibiotic.
  • Effective only against Gram-positive bacteria.
  • Cannot penetrate the outer membrane of Gram-negative bacteria.

Resistance to Vancomycin

• MRSA: Initially treated with vancomycin, but bacteria evolved.
• VISA: Vancomycin Intermediate Staphylococcus aureus.
  • Requires 4-8 times more vancomycin for treatment.
• VRSA: Vancomycin-resistant Staphylococcus aureus.
  • Use of Daptomycin or combinations of antibiotics for treatment.

Vancomycin-Resistant Enterococci (VRE)

• Concern: Significant resistance issue in healthcare settings.
• Common Strains:
  • Enterococcus faecium.
  • Enterococcus faecalis.
• Spread: Nosocomial (hospital-acquired) infections in the U.S.

Conclusion

• Resistance Development: Result of antibiotic use and potential overuse.
• Future Directions: Combination therapies to combat resistance and potentially slow bacterial evolution.

• Note: Continue exploring new antibiotics and treatment strategies to address evolving resistant strains.