Fosfomycin achieves antibacterial activity by inhibiting which bacterial target?
- A Alanine racemase, preventing D-alanine formation
- B The bactoprenol lipid carrier responsible for transporting wall precursors
- C MurA enolpyruvyl transferase, blocking the first committed step of peptidoglycan synthesis ✓
- D Transglycosylation at the growing peptidoglycan chain
Correct answer: C. MurA enolpyruvyl transferase, blocking the first committed step of peptidoglycan synthesis
Explanation
Fosfomycin is a phosphonic acid analogue of phosphoenolpyruvate that covalently inhibits MurA (UDP-N-acetylglucosamine enolpyruvyl transferase), the first cytoplasmic step of peptidoglycan synthesis. Cycloserine inhibits alanine racemase and D-alanine ligase, option A. Bacitracin interferes with the bactoprenol lipid carrier dephosphorylation, option B. Transglycosylation is blocked by vancomycin indirectly. Fosfomycin is used as single-dose oral therapy for uncomplicated cystitis caused by E. coli including ESBL producers.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.