Methicillin-resistant staphylococcus aureus, most often simply referred to as MRSA, causes an infection that is resistant to several common antibiotics. An estimated 90,000 people in the United States fall ill each year from MRSA. However, it is not clear how many die from the infection; one estimate puts it at more than 18,000, which would be slightly higher than U.S. deaths from AIDS. The infection has been associated with health care facilities, where it infects people with weakened immune systems. However, many recent cases involve an aggressive strain, community-associated MRSA, or CA-MRSA. Community-associated MRSA is generally the result of skin-to-skin contact between individuals. The infection can be life threatening if untreated. It is spread through close contact with an infected person, or by touching surfaces or personal items used by infected people. As a result, this disease is common among athletes and people in hospitals and jails. MRSA infections produce abscesses, boils and other pus-filled lesions on the skin.