Overview
Methicillin-resistant Staphylococcus aureus (MRSA) infection is caused by a type of staph bacteria that's become resistant to many of the antibiotics used to treat ordinary staph infections.
MRSA infections that happen in a healthcare setting are often linked to surgery or use of artificial joints or tubing. MRSA that you get during or after being in a healthcare setting can be life-threatening.
MRSA infections that happen in the wider community usually spread by skin-to-skin contact. This infection often starts as a painful skin boil and can most often be treated with antibiotics.
Symptoms
Swollen, painful bumps that look like pimples or spider bites are an early symptom of skin infections caused by staph bacteria, including MRSA. These red bumps can turn into deep, painful boils, also called abscesses.
The area around the bumps may be warm to the touch. It may be filled with thick fluid or leaking the fluid. You also may have a fever.
Staph infections also can happen inside the body. These infections can be life-threatening and happen in bones, joints, surgical wounds, the bloodstream, heart valves and lungs. Symptoms depend on the site of infection.

Staph infection
MRSA infections start out as small red bumps that can quickly turn into deep, painful abscesses.
When to see a doctor
Keep an eye on minor skin problems such as pimples, insect bites, or cuts and scrapes. This is especially important for children. If wounds seem to be infected or there's a wound and a fever, see a healthcare professional.
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Causes
Methicillin-resistant Staphylococcus aureus (MRSA) infection is caused by a type of staph bacteria that that can't be treated by many of the antibiotics used to treat ordinary staph infections. MRSA infection is the result of decades of often unneeded antibiotic use. Even when antibiotics are used properly, they add to the rise of drug-resistant bacteria because they don't destroy every germ they target. Bacteria that survive treatment with one antibiotic soon learn to resist others.
Risk factors
MRSA infection is more likely if a person has already had a MRSA infection or has used antibiotics.Other factors that put someone at risk depend on the chance of contact with staph bacteria.
Healthcare or hospital strains are more common among people who:
- Get care in the hospital. MRSA often affects older adults and people with weakened immune systems.
- Had surgery or use a medical device. Medical tubing such as IV lines or catheters can provide a pathway for MRSA to travel into the body.
- Live in a long-term care facility. People in care facilities may bring MRSA back from a hospital stay. Or MRSA may spread through contact with other patients or healthcare professionals.
Community strains of MRSA are more common among certain groups.
- People who play contact sports. MRSA can spread through cuts and scrapes and skin-to-skin contact.
- People who live in crowded conditions. MRSA outbreaks have occurred in military training camps, child care centers and prisons.
- Men who have sex with men. This group of people has a higher risk of developing MRSA infections.
- People with HIV infection. People with HIV have a higher risk of developing MRSA infections.
- People who use illegal injected drugs. People who use illicit injected drugs have a higher risk of MRSA infections.
Complications
MRSA infections can resist the effects of many common antibiotics. That makes the infections harder to treat. Because they're harder to treat, they spread more easily and sometimes become life-threatening. MRSA infections may affect your bloodstream, lungs, heart, bones or joints.
Prevention
To prevent MRSA infection, follow good hygiene practices.
- Wash your hands. Wash your hands well and often with soap and water for at least 20 seconds. Or use an alcohol-based hand sanitizer with at least 60% alcohol.
- Keep wounds covered. The fluid from infected sores may contain MRSA, so keep cuts and scrapes clean and covered with clean, dry bandages until they heal.
- Keep personal items personal. Don't share personal items that can spread MRSA such as towels, sheets, razors, clothing and athletic equipment.
- Shower after athletic games or practices. Shower right after each game or practice. Use soap and water. Don't share towels.
- Sanitize linens. If you have a cut or sore, wash towels and bed linens in a washing machine set to the hottest water setting, with added bleach, if possible. And dry them in a hot dryer. Wash gym and athletic clothes after each wearing.
People who are in the hospital and who have MRSA infection are often placed apart, in isolation. That helps stop the spread of MRSA. Visitors and healthcare professionals caring for people in isolation may need to follow strict hygiene practices and wear protective garments.