JAC 49/2 pp. 301-308

For several decades there has been a steady increase in the incidence of bacterial infections caused by Gram-positive bacteria. Gram-positive infections have become a serious problem, especially in the nosocomial setting, and the treatment of these infections is complicated by the emergence of multidrug-resistant pathogens. Staphylococci are among the most frequent causes of both communityand hospital-acquired infection, and the prevalence of these infections appears to be increasing. Consequently, the isolation of clinical strains of Staphyloccus aureus exhibiting reduced susceptibility to the glycopeptides is extremely worrying. The rise in antimicrobial resistance among Gram-positive species has highlighted concerns regarding the use of antibiotics and the need for novel agents. One such novel antibiotic is linezolid. Linezolid is the first of a new class of antibiotic, the oxazolidinones, with a unique mechanism of action. Bacterial protein synthesis is inhibited by blocking the formation of ribosomal initiation complexes. This antibiotic has been shown to have a broad spectrum of activity against Gram-positive organisms, including methicillin-resistant S. aureus (MRSA). The effects of linezolid on bacterial biofilms, a common complication of medical device-associated staphylococcal infections, have not as yet been investigated. Biofilm-associated infections are becoming more common, this is largely due to the increase seen in the use of indwelling medical devices. Bacteria found in biofilms typically exhibit increased MICs resulting in reduced susceptibility to antibiotics. It is thought that a number of factors contribute to this increase in resistance, such as a low growth rate and failure of the agent to penetrate the biofilm. The majority of in vitro assessments of antibiotics from which conclusions are