Clavulanic acid restores ampicillin activity against beta-lactamase-producing organisms. What is the primary mechanism by which clavulanic acid achieves this?

• A It inhibits penicillin-binding proteins with higher affinity than ampicillin
• B It prevents the efflux of ampicillin from the bacterial cell
• C It upregulates outer membrane porins to increase ampicillin entry
• D It acts as a suicide (irreversible) inhibitor of bacterial beta-lactamases ✓

Explanation

Clavulanic acid is a beta-lactam that binds covalently and irreversibly to the active site of beta-lactamases — acting as a 'suicide substrate' or mechanism-based inhibitor — thereby protecting ampicillin from enzymatic hydrolysis. It has very weak intrinsic antibacterial activity itself. Efflux pumps and porin downregulation are separate resistance mechanisms not addressed by clavulanic acid.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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