Which classification of antibiotics primarily targets peptidoglycan in the bacterial cell wall?

Which classification of antibiotics primarily targets peptidoglycan in the bacterial cell wall?

• A. Bacitracin
• B. Penicillins
• C. Cephalosporins
• D. Aminoglycosides

Answer: (A)

This question focuses on how antibiotics disrupt bacterial cell wall synthesis. Bacitracin uniquely blocks the early stage of peptidoglycan construction by targeting the lipid carrier bactoprenol phosphate and preventing its dephosphorylation and recycling. Without a recycled bactoprenol carrier, peptidoglycan precursors cannot be transported across the cytoplasmic membrane, so the cell wall cannot be assembled properly and the bacterium becomes vulnerable. Penicillins and cephalosporins, while also affecting the cell wall, work later in the process by inhibiting penicillin-binding proteins and thus blocking cross-linking of the peptidoglycan strands. Aminoglycosides, on the other hand, do not act on the cell wall at all; they inhibit protein synthesis by targeting the 30S ribosomal subunit. Therefore, bacitracin is the best choice because its primary action is on the peptidoglycan synthesis pathway through disruption of the lipid carrier involved in transporting cell wall components.

This question focuses on how antibiotics disrupt bacterial cell wall synthesis. Bacitracin uniquely blocks the early stage of peptidoglycan construction by targeting the lipid carrier bactoprenol phosphate and preventing its dephosphorylation and recycling. Without a recycled bactoprenol carrier, peptidoglycan precursors cannot be transported across the cytoplasmic membrane, so the cell wall cannot be assembled properly and the bacterium becomes vulnerable.

Penicillins and cephalosporins, while also affecting the cell wall, work later in the process by inhibiting penicillin-binding proteins and thus blocking cross-linking of the peptidoglycan strands. Aminoglycosides, on the other hand, do not act on the cell wall at all; they inhibit protein synthesis by targeting the 30S ribosomal subunit.

Therefore, bacitracin is the best choice because its primary action is on the peptidoglycan synthesis pathway through disruption of the lipid carrier involved in transporting cell wall components.