Linezolid is used for MRSA pneumonia. Its unique mechanism distinguishing it from all other protein synthesis inhibitors is:

• A Binding to 30S ribosomal subunit and causing mRNA misreading
• B Inhibiting the 50S peptidyl transferase, blocking peptide elongation
• C Blocking translocation by inhibiting EF-G GTPase activity
• D Binding to 23S rRNA of the 50S subunit and preventing formation of the initiation complex (70S) ✓

Explanation

Linezolid (an oxazolidinone) binds to the 23S rRNA component of the 50S subunit at a unique site and prevents assembly of the 70S initiation complex, blocking the first step of translation — initiation; no other clinical protein synthesis inhibitor acts at this precise step. This distinct mechanism means there is no cross-resistance with other ribosome-targeted antibiotics. Peptidyl transferase inhibition is the mechanism of chloramphenicol.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.