A patient with severe Pseudomonas aeruginosa pneumonia is prescribed piperacillin-tazobactam. Tazobactam is added because it:

• A Has intrinsic anti-pseudomonal activity synergizing with piperacillin
• B Increases piperacillin bioavailability by inhibiting renal tubular secretion
• C Directly disrupts Pseudomonas outer membrane porin channels
• D Inhibits beta-lactamase enzymes as a suicide inhibitor, restoring piperacillin activity ✓

Explanation

Tazobactam is a beta-lactamase inhibitor that acts as a 'suicide substrate' — it irreversibly acylates the active serine of beta-lactamase enzymes, inactivating them and thereby protecting piperacillin from enzymatic degradation. Tazobactam has minimal intrinsic antibacterial activity. This combination is particularly useful for beta-lactamase-producing Gram-negative organisms; however, metallo-beta-lactamases (class B) are not inhibited.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.