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What is MRSA?

MRSA stands for methicillin-resistant Staphylococcus aureus, or Staph aureus (or staph) for short. Staph bacteria are very common. In fact, many people have staph living on their skin or in their nose. This is usually harmless and does not cause a problem. However, MRSA is a dangerous strain of staph that is different. MRSA has become resistant to several antibiotics that normally treat a staph infection. Because of this, MRSA is very hard to kill compared to normal staph bacteria.

In the past, MRSA was mainly a problem in hospitals and other healthcare facilities. This is healthcare-associated or hospital-acquired MRSA (HA-MRSA). It remains one of the most common hospital-acquired infections. However, a new threat has emerged in recent years from MRSA strains in the community. MRSA infections occurring anywhere outside of healthcare facilities is community-acquired MRSA (CA-MRSA). 

HA-MRSA mainly occurs in association with invasive procedures. This includes surgeries, joint replacements, and medical device placements. It can lead to infections at the site, blood infections, and pneumonia. Residents of long-term care facilities are also at risk. 

CA-MRSA spreads mainly through skin-to-skin contact with an infected person. Contaminated items can also spread the bacteria. Typically, CA-MRSA causes a skin infection that can be painful. However, it can quickly invade deeper and become a serious infection and may lead to sepsis.

For CA-MRSA, doctors may drain an abscess or boil and may or may not need to prescribe antibiotics. For more serious infections and HA-MRSA, there are still certain antibiotics that are effective against MRSA.

Complications from CA-MRSA can happen quickly. Seek prompt medical care for signs of a skin infection, such as warm, swollen or tender skin. Seek immediate medical care if fever, confusion, or shortness of breath accompany these signs. Never try to drain a skin abscess or blister yourself, as this can lead to serious complications.

What are the symptoms of MRSA?

CA-MRSA infection often develops near a cut, wound, or open sore. But it can also start on intact skin. 

Common symptoms

Initially, CA-MRSA infection may look like a minor skin problem, with bumps, pimples, or lesions resembling bug bites. Other common MRSA symptoms include skin that is: 

  • Painful or tender

  • Pus-filled or draining pus or other fluid

  • Red

  • Swollen

  • Warm to the touch

Serious symptoms that might indicate a life-threatening condition

In some cases, CA-MRSA can become a serious and even life-threatening infection. Seek immediate medical care (call 911) if you, or someone you are with, have signs of a skin infection or any of the following symptoms:

Seeing your doctor at the first sign of a skin infection can help prevent the infection from becoming serious.

What causes MRSA?

MRSA is the result of many, many years of incorrect antibiotic use. Antibiotics work by targeting processes specific to how bacteria replicate. Resistance develops when bacteria are able to adjust these processes to get around the antibiotic. Bacteria can make these changes very quickly and learn with each new antibiotic exposure. 

Antibiotics are used incorrectly when people take them for viral infections, such as a cold or flu. Antibiotics can only treat bacterial infections. But even with legitimate bacterial infections, people can still use them incorrectly. For example, they don’t finish the entire course of antibiotics their doctor prescribes. In each of these cases, bacteria get exposure to the antibiotic and an opportunity to learn how to grow even in the presence of the drug. Some bacteria survive and pass on the information they gained from the exposure as they replicate.

What are the risk factors for MRSA?

A number of factors increase the risk of developing MRSA. However, risk factors for HA-MRSA and CA-MRSA are different.

Risk factors for HA-MRSA include:

  • Being in a hospital, long-term care home, or other healthcare facility, especially for the elderly, people with weakened immune systems, and people with chronic medical conditions

  • Having surgery or other invasive procedure

  • Needing medical device or tubing placement, such as IVs (intravenous) lines, central lines, and urinary catheters

Risk factors for CA-MRSA include:

  • Being a homosexual man

  • Living in crowded or unclean conditions, such as camps, dorms, jails, and military barracks

  • Participating in contact sports, such as wrestling and football

  • Sharing personal items, such as towels and sports equipment

  • Using IV drugs

  • Working in childcare settings

As an easy way to remember the risk factors, the CDC (Centers for Disease Control and Prevention) came up with the 5 Cs—Crowding, Contact, Compromised skin, Contaminated items, and lack of Cleanliness.

Reducing your risk of MRSA

Hygiene plays a large role in both HA-MRSA and CA-MRSA. Inadequate hand washing by healthcare providers contributes to the spread of MRSA in facilities. So, adequate handwashing is essential to preventing MRSA. When someone has HA-MRSA, putting them in isolation and following infection control procedures can help prevent the spread.

You may be able to lower your risk of CA-MRSA by:

  • Cleaning cuts, wounds, scrapes and open sores daily and covering them with clean, dry bandages

  • Cleaning shared sports equipment before use and protecting your skin with a towel or clothing to prevent contact

  • Not sharing personal items, including towels, razors, uniforms, or clothing that touches the skin

  • Showering right after games or practices

  • Washing athletic clothing and uniforms after every use

  • Washing your hands regularly while you sing the ‘Happy Birthday’ song twice to measure the correct time

If you are in a high-risk group for CA-MRSA, talk with your doctor about ways to prevent it. Make sure you know the warning signs and see your doctor right away for any concerns.

How is MRSA treated?

To find out if MRSA is the cause of an infection, your doctor will need to send a tissue sample or swab to a lab. The lab will grow any bacteria in the sample and test it to identify it. This testing will give your doctor information about antibiotics that can treat the infection. 

For HA-MRSA, there are certain antibiotics that can still treat the infection. In most cases, treatment requires IV antibiotics for an extended amount of time.

For CA-MRSA, treatment may or may not involve antibiotics. Often, doctors are able to drain the infection from an abscess. Keeping the wound clean and applying ointment as directed may be all that is necessary. Sometimes, doctors also need to prescribe oral antibiotics. Be sure to finish the entire course and ask what to do if you miss a dose. Contact your doctor if the infection is not improving or your symptoms get worse.

What are the potential complications of MRSA?

CA-MRSA can lead to serious and life-threatening complications. This includes infections of the bones, blood, heart, lungs, joints, or other organs. People with weakened immune system and the elderly have a higher risk of complications, including death. Infection also can trigger sepsis. Fortunately, complications from CA-MRSA are not common in healthy people who receive prompt and adequate treatment.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Oct 20
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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  9. Sepsis. Mayo Foundation for Medical Education and Research.