Community-Acquired MRSA

What is community-acquired MRSA?

Methicillin-resistant Staphylococcus aureus (MRSA) is a type of bacteria. Bacteria that can’t be killed by the antibiotic methicillin and other similar medicines are called methicillin-resistant. Community-acquired means that you didn’t get the infection in a hospital or other healthcare setting. MRSA infections are sometimes very hard to treat.

Your skin and nasal passages are normally coated by millions of different kinds of bacteria. This is called being colonized with the bacteria. Staphylococcus aureus (commonly known as “staph”) is one such type of germ. It is found in about a third of all people in the U.S. These germs normally don’t cause a problem if your immune system is strong and your skin stays intact. But if your skin is damaged, they can enter the tissue. They might cause a mild infection, like a small pimple. If they spread from the local tissue into the bloodstream, they can cause more widespread problems.

Antibiotics are medicines used to kill a specific type of bacteria. Over time, certain groups of these germs can adapt to the antibiotics. They may no longer respond to them. This is antibiotic resistance. MRSA are a specific subgroup of staph bacteria. They have become resistant to methicillin and other similar antibiotics. To treat MRSA, other kinds of antibiotics must be used.

MRSA infections were first found in healthcare settings, such as hospitals or nursing homes in the 1960s. This was soon after methicillin was first used. This source of MRSA infection is still the most common.

Since the 1990s, more and more healthy people living in the community have become colonized with MRSA. Many of those people get infections from MRSA. But the risk of getting community-acquired MRSA is still small in most communities.

Community-acquired MRSA is more likely to cause serious problems in young children and older adults. That’s also true for people with a weakened immune system.

What causes community-acquired MRSA?

MRSA first developed when many strains of bacteria were exposed to standard antibiotics. It caused the surviving strains to become resistant to the antibiotics.

Many people who are colonized with MRSA don’t know it. You might pick up MRSA by:

  • Touching someone who has MRSA on his or her skin
  • Being nearby when a person colonized with MRSA coughs or sneezes
  • Touching a surface that has MRSA on it
  • Touching the contaminated wound of someone with a MRSA infection

These things might cause you to become colonized with MRSA as well. If MRSA penetrates your skin through a cut or other wound, you might get an active MRSA infection.

Who is at risk for community-acquired MRSA?

Some things that make it more likely for you to get a community-acquired MRSA are:

  • Skin trauma
  • Skin tattoos or body piercings
  • Previous infection with MRSA
  • Close contact with others who have MRSA colonization or infection
  • Sharing equipment or supplies that are not cleaned or laundered between users

Community-acquired MRSA infections are more common in groups of people that spend a lot of time in close quarters. These include:

  • People in prisons
  • People in the military
  • People on an athletic team

You may also have a higher risk of getting it if someone else that you live with already has it. But many people who get a community-acquired MRSA infection have no risk factors for the disease.

What are the symptoms of community-acquired MRSA?

Colonization by MRSA does not lead to symptoms unless the bacteria cause an active infection. Most people who have community-acquired MRSA show symptoms of a skin infection. You might have a raised, red lump or a large, tender lump that drains pus. This area may get bigger and become more and more tender, red, and swollen. In some cases, you might have a bunch of small lumps that look like pimples.

If the MRSA germs enter your bloodstream, it may lead to other problems. These include:

  • Fever
  • Tiredness (fatigue)
  • Pneumonia
  • Infection of the brain or spinal cord (meningitis)
  • Infection of deeper layers of skin and soft tissue
  • Infection of a heart valve
  • Infection of a bone or joint
  • Infection around a medical device such as a pacemaker or IV

These problems may cause other symptoms, like pain and swelling around an infected joint. Or you may suffer from coughing and shortness of breath from MRSA-related pneumonia.

How is community-acquired MRSA diagnosed?

Your healthcare provider will ask about your symptoms and your past health problems, including previous MRSA infections. He or she will also do a physical exam. That includes a careful exam of your affected skin.

If your healthcare provider suspects that you might have a staph infection, you will likely need some tests. Based on your symptoms, these might include:

  • A skin swab of your affected skin, to check it for MRSA
  • X-ray of the lung, if your provider thinks your lungs may be infected
  • Echocardiogram of the heart, if your healthcare provider thinks your heart might be infected
  • CT scan or MRI, to see if any soft tissue, bones, blood cultures, or joints are infected

How is community-acquired MRSA treated?

Antibiotics are the standard treatment for community-acquired MRSA. Many times, you can take an antibiotic by mouth for a week or so to get rid of the infection. You might take trimethoprim-sulfamethoxazole, clindamycin, or doxycycline. You cannot take trimethoprim-sulfamethoxazole if you are allergic to sulfa medicines. If you have a boil, your healthcare provider might also drain the affected area to help it heal. You should not do so on your own. You might spread the infection.

You need to take your antibiotic exactly as prescribed, even if you are feeling better. If you don’t, you may develop an infection that is even harder to treat. You may also raise the risk that others in your community will get MRSA.

If you have severe symptoms, you might need to stay in the hospital during your care. You might need to get similar antibiotics through an IV.

Most people recover from MRSA without any problems. That’s especially true for healthy people who get it in a community setting. If the MRSA infection spreads through the bloodstream, there is a chance that it can cause serious illness and even death.

If you have repeated MRSA infections, your healthcare provider might recommend ways to get rid of the MRSA growing on your body. These might include using mupirocin ointment or chlorhexidine soap.

Can community-acquired MRSA be prevented?

Some cases of community-acquired MRSA can be prevented. You can do so by:

  • Always washing hands thoroughly with soap and water
  • Using tissues to cover your mouth when coughing or sneezing
  • Keeping cuts and scrapes clean and covered until healed
  • Avoiding touching others’ wounds
  • Avoiding sharing personal items, like razors, towels, or brushes
  • Showering after team athletic activities

If you know you are colonized with MRSA, following the above steps can help you from spreading it. If you don’t have MRSA, following them can lower your chances of infection.

When should I call my healthcare provider?

If you have signs of a possible MRSA skin infection, call to see your healthcare provider soon. Also call if you have a MRSA skin infection that has not started to clear up within a week. See a healthcare provider right away if you have major symptoms. These include shortness of breath, high fever, confusion, or swollen, painful joints.

Key points about community-acquired MRSA

  • A MRSA infection is caused by a type of bacteria. It cannot be treated with the standard antibiotics. Community-acquired MRSA is a MRSA infection that you get outside of a healthcare setting.
  • Most commonly, MRSA causes a skin infection.
  • If MRSA germs enter your bloodstream, they can cause major problems, like infection of the heart valves, lungs, or of the bones or joints.
  • Alternative antibiotics are the treatment for MRSA.
  • Infection-control precautions can help prevent the spread of MRSA.

Next steps

Tips to help you get the most from a visit to your health care provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.
Online Medical Reviewer: Foster, Sara M, RN, MPH
Online Medical Reviewer: MMI board-certified, academically affiliated clinician
Last Review Date: 7/27/2015
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