The high rates of antimicrobial resistance seen among many Grampositive pathogens means that there is an ongoing need for new antibacterial drugs. Currently, several pharmaceutical companies are investigating compounds belonging to a new class of anti-Grampositive agents, the oxazolidinones, one member of which, linezolid, is licensed for clinical use. Interest in oxazolidinones is being stimulated by the results of recent trials demonstrating the excellent clinical efficacy of linezolid in a range of infections. Linezolid is also a relatively safe drug, the main toxicity issue relating to development of thrombocytopenia in some patients receiving prolonged courses. With regard to new oxazolidinones, there is particular interest in analogs that, in early laboratory evaluation, show enhanced activity against the respiratory pathogens Haemophilus influenzae and Moraxella catarrhalis. The future potential of the oxazolidinones will depend on the antibacterial spectra, pharmacokinetic properties and toxicity profiles of new compounds, and the degree to which their clinical use may be affected by the emergence of oxazolidinone-resistant pathogens.
