- Vancomycin exerts its antibacterial effect by binding specifically to the D-Ala-D-Ala terminus of the peptidoglycan precursors in the bacterial cell wall.
- This binding prevents cross-linking of peptidoglycan chains by blocking transpeptidase enzymes, leading to inhibition of cell wall synthesis and bacterial death.
- Unlike beta-lactams that target PBPs directly, vancomycin acts earlier by obstructing substrate availability.
- This mechanism is crucial against Gram-positive bacteria with thick peptidoglycan layers.

Reference: “Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases,” 9th Edition, Volume 1, Chapter 39/Page 564