Learn About Methicillin-Resistant Staphylococcus Aureus (MRSA)

Are You at Risk of a MRSA Infection?

MRSA bacterial colonies in a petri dish.
MRSA bacterial colonies in a petri dish. R Parulan Jr./Getty Images

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacteria that is resistant to many common antibiotics and can cause infections on the skin and in the lungs. During the late 1940s through the 1950s, S. Aureus became resistant to penicillin. Methicillin, a form of penicillin, was developed to combat the bacteria. In 1961, scientists discovered that S. Aureus had also become resistant to methicillin.

MRSA has become resistant to the entire class of penicillin-like antibiotics known as beta-lactams. Beta-lactams include penicillin, amoxicillin, oxacillin, and methicillin, among others.

How MRSA Is Spread

MRSA can be spread through casual contact or contact with an object that is contaminated with the bacteria. If MRSA is in the lungs, it will be spread when the infected person coughs, sneezes, or laughs. It can also be spread with objects that have contact with the mouth. If MRSA is on the skin, it can be spread through skin-to-skin contact with the infected person. This type of contamination occurs most commonly with athletes who play contact sports like football or wrestling. MRSA can cause severe problems such as pneumonia, surgical site infections, and a bloodstream infection.

Classifications of MRSA

MRSA is classified according to where the infection was initially acquired. As such, there are two types of MRSA infections:

  1. Hospital-acquired MRSA (HA-MRSA): HA-MRSA is acquired in a hospital. Incidents of MRSA have increased due to the number of patients, both elderly and immune-compromised, an increase in life support treatments, the number of invasive surgical procedures, and failure to maintain infection control measures.
  1. Community-associated MRSA (CA-MRSA): CA-MRSA may be a strain of HA-MRSA that occurs in healthy people who have no interaction with a hospital setting. CA-MRSA develops into a more invasive and life-threatening infection affecting skin or soft tissue. Most people who develop CA-MRSA have skin-to-skin contact, such as athletes, soldiers, inmates, childcare providers, and residents of long-term care facilities.

Causes of MRSA Infection

CA-MRSA most often is caused by the bacteria entering the body through a cut or scrape. It appears as a skin infection, in the form of a boil or abscess. It can sometimes be mistaken for a spider bite. CA-MRSA can become more serious and lead to infections in the bloodstream or pneumonia. Other symptoms may include shortness of breath; fever; chills, and death.

Symptoms of MRSA Infection

Symptoms of MRSA begin with a small bump that may be confused with a spider bite. You may have a fever. The area on the skin that is infected may appear:

  • Red
  • Swollen
  • Painful and warm to the touch
  • Filled with pus

If you suspect you have MRSA, cover the suspicious area with a bandage. Thoroughly wash your hands and contact your doctor.

Diagnosis of MRSA Infection

To fully diagnose MRSA, a sample is obtained from the infected area and sent to a laboratory for testing.

If the diagnosis of MRSA is confirmed, further testing to determine which antibiotic will be effective to treat the infection will be conducted. If you are in a hospital setting, you may be tested for MRSA if you are showing signs of infection.

Treatment of MRSA

Treatment of MRSA may include draining the infected area by your doctor. Before prescribing an antibiotic, a sample will be sent to a laboratory to test for resistance to the antibiotic. If the sample is positive for MRSA, you will be prescribed an antibiotic that is not a beta-lactam antibiotic. Make sure you take all of the prescribed doses unless otherwise advised by your doctor.

For severe cases of MRSA, you may need an antibiotic administered intravenously.

Prevention of MRSA

There are steps you can take to reduce your risk of becoming infected with MRSA. They include:

  • Practicing good hygiene by using soap and water or an alcohol-based hand gel
  • Coughing into an elbow or tissue
  • Keeping cuts and scrapes clean and covered until healed
  • Avoiding contact with other people’s wounds or bandages
  • Avoiding sharing personal items such as razors, towels, clothing, cups, or toothbrushes
  • Washing soiled sheets, towels, clothing in hot water with bleach and drying them in a hot dryer
  • Cleaning exercise equipment before and after use with a disinfectant or alcohol-based cleaner
  • Using a clean towel between your skin and shared exercise equipment


Cystic Fibrosis Foundation

National institute of Allergy and Infectious Diseases

Centers for Disease Control and Prevention


National foundation for Infectious Diseases

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