What is the mechanism of action for Vancomycin?

• A. Inhibits bacterial protein synthesis
• B. Disrupts bacterial cell membrane
• C. Inhibits bacterial cell wall synthesis
• D. Inhibits DNA replication

Answer: (C)

Vancomycin primarily works by inhibiting bacterial cell wall synthesis. This is crucial because the integrity of the bacterial cell wall is essential for maintaining the cell's shape and protecting it from environmental stress. Vancomycin binds specifically to the D-alanyl-D-alanine terminus of the peptidoglycan precursors, preventing their incorporation into the growing cell wall. This disruption ultimately leads to cell lysis and death, particularly in Gram-positive bacteria, which are more susceptible due to their thick peptidoglycan layer.

Other mechanisms that involve inhibiting protein synthesis, disrupting the cell membrane, or inhibiting DNA replication do not describe how Vancomycin functions. For instance, while other antibiotics might act on the ribosomal units to inhibit protein synthesis, Vancomycin does not interact with ribosomes. Furthermore, it does not target the cell membrane directly or interfere with DNA processes. This specificity makes Vancomycin effective for treating infections caused by certain Gram-positive organisms, including methicillin-resistant Staphylococcus aureus (MRSA).