MRSA stands for methicillin-resistant Staphylococcus aureus.MRSA is a "staph" germ that does not get better with the type of antibiotics that usually cure staph infections.
When this occurs, the germ is said to be "resistant" to the antibiotic.
Most staph germs are spread by skin-to-skin contact (touching). A doctor, nurse, other health care provider, or visitors to a hospital may have staph germs on their body that can spread to a patient.
Once the staph germ enters the body, it can spread to bones, joints, the blood, or any organ, such as the lungs, heart, or brain.
Serious staph infections are more common in people with a weakened immune system. This includes patients who:
- Are in hospitals and long-term care facilities for a long time
- Are on kidney dialysis (hemodialysis)
- Receive cancer treatment or medicines that weaken their immune system
- Inject illegal drugs
- Had surgery in the past year
MRSA infections can also occur in healthy people who have not recently been in the hospital. Most of these MRSA infections are on the skin, or less commonly, in the lung. People who may be at risk are:
- Athletes and others who share items such as towels or razors
- Children in day care
- Members of the military
- People who have gotten tattoos
It is normal for healthy people to have staph on their skin. Many of us do. Most of the time, it does not cause an infection or any symptoms. This is called "colonization" or "being colonized." Someone who is colonized with MRSA can spread it to other people.
A sign of a staph skin infection is a red, swollen, and painful area on the skin. Pus or other fluids may drain from this area. It may look like a boil. These symptoms are more likely to occur if the skin has been cut or rubbed, because this gives the MRSA germ a way to "get in." Symptoms are also more likely in areas where there is more body hair, because the germ can get into hair follicles.
MRSA infection in patients who are in health care facilities tend to be severe. These staph infections may be in the bloodstream, heart, lungs or other organs, urine, or in the area of a recent surgery. Some symptoms of these severe infections include:
- Chest pain
- Cough or shortness of breath
- Fever and chills
- General ill feeling
- Wounds that do not heal
Exams and Tests
The only way to know for sure if you have a MRSA or staph infection is to see a health care provider.
A cotton swab is used to collect a sample from an open skin rash or skin sore. Or, a sample of blood, urine, sputum (spit), or pus from an abscess may be collected. The sample is sent to a lab to test for staph and MRSA. If MRSA is found, it will be tested to see which antibiotic should be used to treat your infection.
Draining the infection may be the only treatment needed for a skin MRSA infection that has not spread. A health care provider should do this procedure. Do not try to pop open or drain the infection yourself. Keep any sore or wound covered with a clean bandage.
Severe MRSA infections are becoming harder to treat. Your lab test results will tell the doctor which antibiotic will treat your infection. Your doctor will follow guidelines about which antibiotics to use, and will look at your personal health history. MRSA infections are harder to treat if they occur in:
- The lungs or blood
- People who are already ill or who have a weak immune system
You may need to keep taking antibiotics for a long time, even after you leave the hospital.
For more information about MRSA, see the Centers for Disease Control web site: www.cdc.gov/mrsa/.
When to Contact a Medical Professional
Call your health care provider if you have a wound that seems to get worse instead of healing.
Follow these steps to avoid a staph infection and to prevent an infection from spreading:
- Keep your hands clean by washing them thoroughly with soap and water. Or, use an alcohol-based hand sanitizer.
- Keep cuts and scrapes clean and covered with bandages until they heal.
- Avoid contact with other people's wounds or bandages.
- Do NOT share personal items such as towels, clothing, or cosmetics.
Simple steps for athletes include:
- Cover wounds with a clean bandage. Do NOT touch other people's bandages.
- Wash your hands well before and after playing sports.
- Shower right after exercising. Do NOT share soap, razors, or towels.
- If you share sports equipment, clean it first with antiseptic solution or wipes. Place clothing or a towel between your skin and the equipment.
- Do NOT use a common whirlpool or sauna if another person with an open sore used it. Always use clothing or a towel as a barrier.
- Do NOT share splints, bandages, or braces.
- Check that shared shower facilities are clean. If they are not clean, shower at home.
If you have surgery planned, tell your health care provider if:
- You have frequent infections
- You have had a MRSA infection before
Methicillin-resistant Staphylococcus aureus; Hospital-acquired MRSA (HA-MRSA)
Centers for Disease Control and Prevention. Methicillin-resistant Staphylococcus aureus (MRSA) infections. Treating MRSA skin and soft tissue infections in outpatient settings. Available at www.cdc.gov/mrsa/index.html. Updated September 10, 2013. Accessed August 16, 2014.
Fishman N, Calfee DP. Prevention and control of health care-associated infections. In: Goldman L, Schafer AI, eds.Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 290.
Fort GL. Methicillin-resistant Staphylococcus aureus. In: Alvero R, Borkan JM, Ferri FF, et al., eds. Ferri's Clinical Advisor. 1st ed. Philadelphia, PA: Elsevier Mosby; 2014:Section I.
Liu C, Bayer A, Cosgrove SE, et al. Clinical practice guidelines by the Infectious Diseases Society of America for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children: executive summary. Clin Infect Dis. 2011;52:285-292.
Que YA, Moreillon P. Staphylococcus aureus (including staphylococcal toxic shock). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2009:chap 195.
Update Date 5/12/2014
Updated by: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial Team.