Linezolid: a new antibiotic.

The U.S. Food and Drug Administration recently approved linezolid for the treatment of patients with methicillin-resistant staphylococcal and vancomycin-resistant enterococcal infections. This oxazolidinone antibacterial agent represents the first approved antibiotic of a new structural class in 35 years. Linezolid is a synthetic compound that acts by inhibiting the initiation complex formation in bacterial protein synthesis, a mechanism of action distinct from other commercially available antibiotics. Thus, cross-resistance between linezolid and other current antimicrobial agents has not been demonstrated to date. Linezolid has a wide spectrum of in vitro activity against Gram-positive organisms, including methicillin-resistant staphylococci, penicillin-resistant pneumococci and vancomycin-resistant enterococci. Some anaerobes, such as Clostridium spp., Peptostreptococcus spp. and Prevotella spp. are also susceptible to linezolid. In addition, linezolid has exhibited good efficacy in experimental animal models of acute otitis media, endocarditis and meningitis due to many common aerobic Gram-positive bacteria. In clinical trials involving hospitalized patients with skin/soft tissue infections, community-acquired pneumonia and serious Gram-positive bacterial infections, linezolid appeared to be an effective treatment option, comparable in efficacy to vancomycin.