A methicillin-resistant staphylococcus aureus (MRSA) infection is caused by a bacteria that resists many antibiotics that are used to treat infections . The bacteria can affect the skin, blood, bones, or lungs. A person can either be infected or colonized with MRSA. When a person is infected, the bacteria cause symptoms. A person colonized also has the bacteria, but it may not cause any symptoms. An MRSA infection can be serious because of the resistance to antibiotics.

There are two types of MRSA infection: community-acquired and nosocomial. People who have a community-acquired MRSA infection were infected outside of a hospital setting. Nosocomial MRSA infections occur in healthcare settings such as hospitals or clinics.

An MRSA infection is caused by a bacteria. The cause of the resistance to the bacteria is from excessive exposure to antibiotics over time. The bacteria adapts to the antibiotics.