Within the past 7 years, the incidence of methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile infections has significantly increased. Risk factors for MRSA infection include previous antibiotic therapy and living arrangements such as prisons or military barracks that involve close, frequent contact with infected persons. Treat stable patients with MRSA skin infections with oral antibiotics in addition to incision and drainage; hospitalization and intravenous antibiotics are recommended for patients whose condition is unstable or who are unlikely to adhere to an oral regimen. A new strain of C difficile, BI/NAP1, has been associated with recurrent infection; more severe disease that mandates urgent colectomy; and dramatically higher mortality in vulnerable populations, such as older adults. Although oral metronidazole has been the mainstay of treatment of C difficile infection, oral vancomycin may be slightly more effective in patients with severe disease.