Bacitracin primarily provides coverage against which type of bacteria?

Bacitracin primarily provides coverage against which type of bacteria?

• A. Gram positive
• B. Gram negative
• C. Both
• D. Neither

Answer: (A)

Bacitracin acts by blocking a key step in peptidoglycan synthesis: it inhibits the dephosphorylation of bactoprenol, the lipid carrier that shuttles cell-wall precursors across the membrane. This disruption prevents proper cell-wall formation, which most effectively affects bacteria that rely heavily on surface-accessible cell-wall synthesis, namely Gram-positive organisms. Gram-positive bacteria lack the outer membrane that blocks many antibiotics, so bacitracin can reach its target more readily and kill them. Grams-negative bacteria, with their outer membrane barrier, are much less susceptible, so bacitracin has little activity against them. Clinically, bacitracin is often used topically (and in combination products) because systemic use carries toxicity risks, reinforcing its role as a primarily Gram-positive selective agent.

Bacitracin acts by blocking a key step in peptidoglycan synthesis: it inhibits the dephosphorylation of bactoprenol, the lipid carrier that shuttles cell-wall precursors across the membrane. This disruption prevents proper cell-wall formation, which most effectively affects bacteria that rely heavily on surface-accessible cell-wall synthesis, namely Gram-positive organisms. Gram-positive bacteria lack the outer membrane that blocks many antibiotics, so bacitracin can reach its target more readily and kill them. Grams-negative bacteria, with their outer membrane barrier, are much less susceptible, so bacitracin has little activity against them. Clinically, bacitracin is often used topically (and in combination products) because systemic use carries toxicity risks, reinforcing its role as a primarily Gram-positive selective agent.