As new drugs to control bacterial pathogens are developed, the organisms evolve to survive. Staphylococcus aureus, a common organism, has steadily developed resistance to antibiotics. For more than 40 years, resistant S. aureus presented a formidable problem to hospitalized patients; in the past decade, however, it has begun to appear outside the clinical setting-often in young people without significant medical conditions. Early diagnosis, appropriate control measures, and proper antibiotic choice can limit the spread and severity of infection.