MRSA stands for "methicillin-resistant staphylococcus aureus." It's an infection with a strain of bacteria that's resistant to certain antibiotics.    Some people who are exposed to MRSA become "colonized," which means that the bacteria are present, growing and multiply without observable signs of disease. MRSA colonization occurs on the skin's surface, in the nasal passages, in sputum or in urine. Other individuals who are exposed to MRSA never become colonized. MRSA colonization may precede or lead to infection in persons with weakened immune systems.    For more detailed information on MRSA, see:   MRSA Infection http://www.healthcentral.com/ency/408/007261.html   What is MRSA? http://www.healthcentral.com/chronic-pain/c/question/16913/28280   Drug-Resistant Staph Infections Reaching Epidemic Levels in Some Parts of U.S. http://www.healthcentral.com/newsdetail/408/609284_3.html   I hope you find this to be helpful.   - MG