Methicillin-Resistant Staphylococcus Aureus (MRSA)

Overview

What is MRSA?

MRSA stands for Methicillin-resistant Staphylococcus aureus. It is a type of Staphylococcus aureus bacterium. These bacteria are resistant to common antibiotics, including methicillin. You may have read about MRSA being a superbug.

What is Staphylococcus aureus (staph)?

Staphylococcus aureus (staph) bacteria live in the nose or on skin. You can harbor staph bacteria, including MRSA, and not know it. A healthcare expert might refer to this as bacterial colonization.

Colonized people (carriers) may one day develop an MRSA infection, or they might stay healthy.

Staph, including MRSA, bacteria live in these body parts:

  • Armpits.
  • Buttocks (your butt).
  • Groin.
  • Nose.

How common is MRSA?

Approximately 1 in 3 Americans are carriers of staph bacteria at any time. Up to half of these could be MRSA. It's important to emphasize that Staph aureus or MRSA carriage is not a disease.

What are the types of MRSA infections?

Two categories of MRSA are:

  • Hospital-associated (HA): HA-MRSA refers to MRSA infections that are associated with healthcare settings, such as hospitals and nursing homes.
  • Community-associated (CA): CA-MRSA infections are those that occur in people who have not had a recent hospitalization or other contact with the healthcare system.

Who is at risk for MRSA infection?

MRSA infection affects all ages and genders. Animals can carry MRSA, although they often get it from people. Intravenous drug users who share needles are 16 times more likely to get MRSA infection.

Certain workers and members of the community are more at risk for MRSA infection. These include:

  • Athletes.
  • Healthcare professionals.
  • Members of the military.
  • Prison inmates.
  • Students and employees at schools and child care centers.
  • Veterinarians, farm workers and livestock workers.

Symptoms and Causes

What is the relationship between MRSA colonization and infection?

Many people who carry MRSA never get sick. The bacterium remains within the skin or mucosa where it has established colonization. Problems arise when MRSA on the skin surface in a colonized person enters the skin through a wound or other opening and invades deeper structures.

How does MRSA spread?

You can get colonized with MRSA through direct contact with an infected person or animal. MRSA can survive on surfaces for hours, sometimes weeks. You can pick up the bacteria by touching or sharing contaminated items, such as:

  • Bedsheets.
  • Clothes.
  • Medical equipment.
  • Sports equipment.
  • Towels.
  • Utensils.

What are the symptoms of MRSA infection?

MRSA can cause a skin rash or infection that looks like a spider bite or pimples. The red, swollen bumps may feel warm and be tender to touch. The rash may ooze.

MRSA can also cause deeper infections in different parts of the body. In severe infections the bacterium may invade the bloodstream, a situation which would be called a bloodstream infection. Symptoms of bloodstream infection include fever and chills.

Diagnosis and Tests

How is MRSA infection diagnosed?

To diagnose an MRSA infection, your healthcare provider will take a small sample of skin or discharge from an open wound. Your provider may order a blood test called a blood culture. A lab checks for MRSA in these samples.

Management and Treatment

What are different forms of MRSA infection?

MRSA infections can occur at various sites and may be serious, even life-threatening. Important MRSA infections include:

How is MRSA infection managed or treated?

The two principles of treating Staph aureus infections, including MRSA infections, are source control and antibiotic therapy:

  • Source control: This refers to reducing the numbers of bacteria at the site of infection. In the case of skin infections, your provider may drain boils or abscesses. Other deeper infections may require more complicated surgery.
  • Antibiotic treatment: The antibiotic used to treat the infection depends on whether the Staph aureus infection is or is not an MRSA infection.

What should I know about MRSA treatments?

Milder infections can be treated with oral antibiotics (antibiotic pills). More severe infections may require intravenous antibiotic treatment. It is very important to take all of the antibiotics exactly as your healthcare provider prescribes.

You should also call your provider if an infection doesn’t start to clear up within a few days of taking a prescribed antibiotic. You may need to go to the hospital for stronger intravenous antibiotics.

Prevention

How can I prevent MRSA infections?

You can lower your risk of getting MRSA by taking these steps:

  • Keep wounds clean and bandaged.
  • Don’t share personal items like towels and razors.
  • Place a towel on a locker room bench before sitting on it naked.
  • Regularly wash sheets, towels and workout clothes in the recommended water temperature. (Hot water isn’t necessary.) Dry everything in a dryer. You don’t need to use bleach or wash potentially contaminated items separately.
  • Shower immediately after working out or participating in activities that increase your risk of MRSA exposure.
  • Use disinfecting sprays that kill germs to wipe down high-touch areas like light switches, remote controls and athletic equipment. Check labels to find disinfectants that kill staph bacteria.
  • Wash hands with hot water and soap for at least 20 seconds. Use alcohol-based hand sanitizer when hand-washing isn’t possible.

Outlook / Prognosis

What is the prognosis (outlook) for people who have a MRSA infection?

Most MRSA skin infections clear up with treatment. MRSA is most dangerous if it enters the bloodstream. MRSA bloodstream infections can be serious. A bloodstream infection requires immediate medical attention.

Living With

When should I call the doctor?

You should call your healthcare provider if you experience:

  • Fever and chills.
  • Infection that doesn’t improve after a few days of antibiotics.
  • Rash.
  • Signs of skin infection (abscesses or boils).

What questions should I ask my doctor?

You may want to ask your healthcare provider:

  • What is the best treatment?
  • What are treatment side effects?
  • What should I do if I forget to take the medicine?
  • What are signs of complications of the infection?

A note from Cleveland Clinic

Many people carry Staph aureus or MRSA bacteria in their skin or noses for varying periods of time and never know it. This is not a problem. In some people, MRSA bacteria cause painful skin infections or more serious invasive infections. People in hospitals or nursing homes are at increased risk for MRSA infections. But you can pick up the bacteria in community settings, too. Contact your healthcare provider if you develop a skin infection or show signs of MRSA.

Last reviewed by a Cleveland Clinic medical professional on 01/19/2021.

References

  • American Academy of Family Physicians. . Accessed 11/16/2020.Methicillin-resistant Staphylococcus aureus (MRSA) (https://familydoctor.org/condition/methicillin-resistant-staphylococcus-aureus-mrsa)
  • Centers for Disease Control and Prevention (CDC). Accessed 11/16/2020.Methicillin-resistant Staphylococcus aureus (MRSA): Cleaning and Disinfection. (https://www.cdc.gov/mrsa/community/environment/index.html)
  • MedlinePlus. Accessed 11/16/2020.MRSA Tests. (https://medlineplus.gov/lab-tests/mrsa-tests/)
  • Merck Manual. . Accessed 11/16/2020.Staphylococcus aureus infections (staph infections) (https://www.merckmanuals.com/home/quick-facts-infections/bacterial-infections-gram-positive-bacteria/staphylococcus-aureus-infections)
  • National Health Services (UK). . Accessed 11/16/2020.MRSA (https://www.nhs.uk/conditions/mrsa/)
  • National Institute for Occupational Safety and Health. Accessed 11/16/2020. MRSA and the Workplace. (https://www.cdc.gov/niosh/topics/mrsa/)

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