Which antimicrobial acts by inhibiting cell wall synthesis?

Which antimicrobial acts by inhibiting cell wall synthesis?

• A. Clindamycin
• B. Gentamicin
• C. Nalidixic acid
• D. Vancomycin

Answer: (D)

Vancomycin acts by blocking cell wall synthesis. It binds to the D-Ala-D-Ala terminus of the peptidoglycan precursors, preventing proper cross-linking of the cell wall. This weakens the wall and leads to bacterial lysis, especially in Gram-positive organisms that rely on thick peptidoglycan layers. The other drugs disrupt other targets: clindamycin and gentamicin inhibit protein synthesis by targeting ribosomal subunits, while nalidixic acid inhibits DNA gyrase and blocks DNA replication.

Vancomycin acts by blocking cell wall synthesis. It binds to the D-Ala-D-Ala terminus of the peptidoglycan precursors, preventing proper cross-linking of the cell wall. This weakens the wall and leads to bacterial lysis, especially in Gram-positive organisms that rely on thick peptidoglycan layers. The other drugs disrupt other targets: clindamycin and gentamicin inhibit protein synthesis by targeting ribosomal subunits, while nalidixic acid inhibits DNA gyrase and blocks DNA replication.