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Methicillin-resistant Staphylococcus aureus (MRSA)

Methicillin-resistant Staphylococcus aureus; Hospital-acquired MRSA (HA-MRSA); Staph - MRSA; Staphylococcal - MRSA

MRSA stands for methicillin-resistant Staphylococcus aureus. MRSA is a "staph" germ (bacteria) 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 certain antibiotics.

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Causes

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 chronic (long-term) medical problems. These include those 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

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
• People who inject illegal drugs
• People who had surgery in the past year
• Children in day care
• Members of the military
• People who have gotten tattoos
• Recent influenza infection

Symptoms

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 enter your body. Symptoms are also more likely in areas where there is more body hair, because the germ can get into hair follicles.

MRSA infection in people who are in health care facilities tends to be severe. These 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 may include:

• Chest pain
• Cough or shortness of breath
• Fatigue
• Fever and chills
• General ill feeling
• Headache
• Rash
• 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 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, or pus from an abscess may be collected. The sample is sent to a lab to test for identification of which bacteria are present, including staph. If staph is found, it will be tested to see which antibiotics are and are not effective against it. This process helps tell if MRSA is present and which antibiotics can be used to treat the infection.

Treatment

Draining the infection may be the only treatment needed for a skin MRSA infection that has not spread. A 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 provider 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.

Be sure to follow instructions on how to care for your infection at home.

Support Groups

For more information about MRSA, see the Centers for Disease Control website: www.cdc.gov/mrsa/about/index.html

Outlook (Prognosis)

How well a person does depends on how severe the infection is, and the person's overall health. Pneumonia and bloodstream infections due to MRSA are linked with high death rates.

When to Contact a Medical Professional

Contact your provider right away if you have a wound that is getting worse instead of healing.

Prevention

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.
• Wash your hands as soon as possible after leaving a healthcare facility.
• 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 provider if:

• You have frequent infections
• You have had a MRSA infection before

Related Information

References

Centers for Disease Control and Prevention website. Methicillin-resistant Staphylococcus aureus (MRSA). www.cdc.gov/mrsa/index.html. Updated February 5, 2019. Accessed December 15, 2022.

Que Y-A, Moreillon P. Staphylococcus aureus (including staphylococcal toxic shock syndrome). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 194.

Review Date: 7/1/2022  

Reviewed By: Internal review and update on 07/01/2022 by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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