oxazolidinone

Oxazolidinones are a class of synthetic antibiotics characterized by a five-membered heterocycle, the 1,3-oxazolidin-2-one ring. This core structure is often augmented with side chains that confer activity against Gram-positive bacteria. The most widely used oxazolidinones are linezolid and tedizolid.

Mechanism of action: They inhibit protein synthesis by binding to the peptidyl transferase center of the 50S ribosomal subunit, interfering with the formation of the 70S initiation complex and preventing the recruitment of aminoacyl-tRNA. This action is generally bacteriostatic against many Gram-positive pathogens; the bactericidal versus specific organisms can vary.

Clinical use and spectrum: Oxazolidinones are active against many Gram-positive pathogens, including MRSA and vancomycin-resistant enterococci. They are used for skin and soft tissue infections, pneumonia, and certain bloodstream infections, particularly when resistance to other agents is a concern or when beta-lactams or glycopeptides are unsuitable. Linezolid was approved for clinical use in 2000; tedizolid is a later-generation agent with a similar spectrum and dosing considerations.

Safety and resistance: Common adverse effects include bone marrow suppression (notably thrombocytopenia) with prolonged therapy, anemia, and peripheral neuropathy. Linezolid has reversible monoamine oxidase inhibition, creating potential interactions with serotonergic or other drugs and with tyramine-containing foods, with risk of serotonin syndrome or hypertensive reactions. Resistance can arise from mutations in the 23S rRNA or ribosomal proteins L3/L4, reducing drug binding; cross-resistance is possible but not universal.