Methicillin-resistant Staphylococcus aureus (MRSA)

Last Updated August 2022 | This article was created by editorial staff and reviewed by Leisa Bailey, MD

What is methicillin-resistant Staphylococcus aureus (MRSA)?

Methicillin-resistant Staphylococcus aureus (commonly known as MRSA) is a subset of bacterial (staph) infection of the skin. Staph is the common name for the bacteria named Staphylococcus aureus. What makes MRSA different from a typical staph infection is its resistance to the antibiotic methicillin and other common antibiotics, such as amoxicillin, oxacillin, and penicillin. This means these antibiotics do not work on the infection. That’s why an MRSA infection is so difficult to treat.

Two main types of MRSA are community-associated MRSA (CA-MRSA) and health care-associated MRSA (HA-MRSA).

Symptoms of MRSA

MRSA skin infections include:

  • Bumps that look like pimples and boils
  • Red at the site
  • Swelling
  • Pain
  • Warm to the touch at the site
  • The bumps may be filled with pus or other drainage
  • Fever

Cuts, scrapes, and hairy areas of the body are common places for MRSA infections to occur.

Bumps from MRSA skin infections can quickly turn into pus-filled abscesses. These are deep, infected wounds. The bacteria may stay in the skin. They can also spread deep in the body. This could cause possibly life-threatening infections such as pneumonia. If they are not treated properly, MRSA infections can cause sepsis. This is a life-threatening reaction to severe infection in the body which weakens your organs.

If you or a family member experiences MRSA symptoms, it is important to call your family doctor immediately. This is especially important if the symptoms include fever. Do not pick at the infected skin or try to treat it yourself. Be sure to cover the area with a bandage. Wash your hands with soap before and after bandaging the wound.

What causes MRSA?

The MRSA infection is spread through contact with an infected person. This could be skin-to-skin contact or from personal items that have touched the infected skin.

HA-MRSA can spread when health care workers don’t wash their hands well between seeing patients. To kill all the bacteria, hands must be washed thoroughly using soap and water or an alcohol-based hand sanitizer. If this isn’t done, the bacteria can spread from infected patients to healthy ones.

People in hospitals, health care facilities, and nursing homes who have weak immune systems are at risk of more serious complications if they get HA-MRSA. Many things can weaken a person’s immune system. Some chemotherapy drugs and medicines taken after an organ transplant can weaken the immune system. So can having the human immunodeficiency virus (HIV). Risk factors for getting HA-MRSA include:

  • Having surgery
  • Having a medical device implanted (such as a catheter)
  • Having recent antibiotic treatment

CA-MRSA is spread through:

  • Overcrowding (as in schools or event venues)
  • Frequent skin-to-skin contact
  • Compromised skin, such as skin with cuts or scrapes
  • Contaminated items and surfaces
  • Lack of cleanliness

Daycare centers, dormitories, jails, locker rooms, military barracks, prisons, and schools are common locations for the CA-MRSA.

MRSA outbreaks have also occurred among members of sports teams. This is because skin-to-skin contact, sharing equipment, and minor cuts and scrapes occur frequently.

How is MRSA diagnosed?

Several tests can show if you have MRSA. Your doctor may take a sample from your wound or nasal passages. They may also take a sample of urine or blood to send to the laboratory. Results of this type of test (called a culture) should be ready in about 24 to 48 hours. It can take about 48 hours for the bacteria to grow. A newer rapid blood test provides results more quickly, in about 2 hours.

Can MRSA be prevented or avoided?

Good hygiene is the best way to avoid MRSA and other bacterial infections:

  • Wash your hands often, using soap and water or an alcohol-based hand sanitizer.
  • If you have any cuts or scrapes, keep them clean and covered with a bandage until they heal.
  • Avoid contact with other people’s wounds or bandages.
  • Don’t share personal items such as razors, towels, and washcloths.
  • Put a towel or other block between you and any other surfaces, such as sitting on a towel in the locker room.

MRSA treatment

In serious cases, some strains of MRSA respond to antibiotics. Take all the doses of the medicine, even if you’re feeling better, unless your doctor tells you otherwise. Contact your doctor if you do not improve after a few days or if the infection gets worse.

For mild cases of MRSA, your doctor may drain the skin boil or abscess and cover the wound with a clean dressing or bandage. The dressing will need to be changed regularly. Your doctor may also prescribe an ointment to apply to the area. Often, this is all that is needed to treat the infection. Schedule a follow-up visit to make sure the site is healing well. Call your doctor if you don’t see any improvement after a few days.

Follow your doctor’s instructions for caring for your infection:

  • Keep the area covered until it’s healed.
  • Change the dressing as advised.
  • Wear disposable gloves to prevent spreading the infection.
  • Throw away bandages and tape with the regular trash. (If heavily soiled, first place inside a separate bag.)
  • Wash your hands often, using soap and water or an alcohol-based hand sanitizer.
  • Don’t share any personal items, such as bed or bath linens, clothing, razors, makeup, or sports or office equipment.

If your clothing, sheets, or towels are contaminated with the MRSA bacteria, wash them in hot water (at least 160°F) and laundry detergent. Use a hot dryer rather than air drying. Clean surfaces with household cleaners.

You may need to be hospitalized if:

  • You have a severe case of MRSA
  • You have other health problems
  • Your infection is life-threatening
  • Your infection may cause the loss of a limb

When you’re in the hospital, you will be monitored closely and receive powerful antibiotics. These are called broad-spectrum antibiotics because they are designed to fight a wide range of infections.

Living with MRSA

Healthy people who develop MRSA skin infections rarely develop more serious problems. But people who have weak immune systems and who get HA-MRSA can develop serious, even life-threatening infections.

MRSA can be carried in the nasal passages and spread even if you don’t know you have it and don’t have any symptoms. If you have frequent MRSA infections, your doctor may want to perform a nasal swab to see if your family members are carriers of MRSA.

Questions to ask your doctor

  • I work at a hospital. What can I do to prevent MRSA?
  • My husband has MRSA. What can I do to protect myself and my family from getting it?
  • How should I care for my wound that was just drained?
  • Should I get rid of my bed linens?
  • Is there any special way I should get rid of my bandages and wound dressings?
  • I have HIV. What should I do if I get infected with MRSA?
  • Someone at my child’s daycare was just diagnosed with MRSA. Should I have my child tested for it?


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