Vancomycin covers which bacteria?

Vancomycin covers which bacteria?

• A. Pseudomonas aeruginosa
• B. Streptococcus pneumoniae
• C. MRSA and Enterococcus
• D. Escherichia coli

Answer: (C)

Vancomycin is active primarily against Gram-positive bacteria, with strong activity against MRSA and susceptible Enterococcus species. It works by binding the D-Ala-D-Ala terminus of cell wall precursors, blocking peptidoglycan synthesis and causing bacterial death in these Gram-positive organisms. Why the other organisms don’t fit: Pseudomonas aeruginosa and Escherichia coli are Gram-negative bacteria. Their outer membrane and different cell wall structure prevent vancomycin from reaching its target, so this drug has little to no activity against them. Keep in mind that some Enterococcus strains can be resistant to vancomycin (VRE), so susceptibility matters in practice.

Vancomycin is active primarily against Gram-positive bacteria, with strong activity against MRSA and susceptible Enterococcus species. It works by binding the D-Ala-D-Ala terminus of cell wall precursors, blocking peptidoglycan synthesis and causing bacterial death in these Gram-positive organisms.

Why the other organisms don’t fit: Pseudomonas aeruginosa and Escherichia coli are Gram-negative bacteria. Their outer membrane and different cell wall structure prevent vancomycin from reaching its target, so this drug has little to no activity against them. Keep in mind that some Enterococcus strains can be resistant to vancomycin (VRE), so susceptibility matters in practice.