USMLE Step 2 Antibiotics and Treatments Practice Exam

Linezolid exerts its antibacterial effects primarily through the inhibition of bacterial protein synthesis. It specifically binds to the 50S ribosomal subunit of bacterial ribosomes, which is crucial for protein synthesis. This binding inhibits the formation of the initiation complex and prevents the proper assembly of the ribosomal subunits necessary for translating mRNA into proteins.

This mechanism is particularly effective against Gram-positive bacteria, including strains that are resistant to other antibiotics, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). By targeting the 50S subunit, linezolid disrupts the critical process of translation, ultimately leading to a decrease in bacterial growth and replication.

Understanding linezolid's mode of action is important, especially in clinical scenarios where other antibiotic options are limited due to resistance patterns.