MRSA stands for methicillin-resistant Staphylococcus aureus. It is a type of staph bacteria. Many people have staph bacteria living on their skin or in their noses. These bacteria usually dont cause any harm. But when staph enters the body through a cut scrape or other open wound it can cause a skin infection. Most staph skin infections are minor and heal on their own or after treatment with antibiotics. A MRSA test looks for the MRSA bacteria in a sample from a wound nostril or other body fluid. MRSA can be treated with special powerful antibiotics. If left untreated a MRSA infection can lead to serious illness or death.