What are MRSA tests?

A MRSA test looks for MRSA bacteria in a sample of fluid or tissue from your body. The sample is often taken from your nose or a wound. MRSA stands for methicillin-resistant Staphylococcus aureus. It is a type of staph bacteria.

Many people have MRSA or other staph bacteria living on their skin or in their noses. These bacteria usually don't cause any harm. Having the bacteria without an infection is sometimes called "carrying" or being "colonized" with the bacteria. But even when you don't have an infection, you could still spread the bacteria to others.

But staph bacteria that enters your body through a cut, scrape, or other open wound, often causes a skin infection. Most staph skin infections are minor. They usually heal on their own or after treatment with antibiotics. But if you are carrying the MRSA bacteria on your skin and it enters through an open wound, the usual treatments may not work well.

MRSA bacteria are different than other staph bacteria. In a normal staph infection, antibiotics will kill the bacteria and stop them from growing. In a MRSA infection, the antibiotics usually used to treat staph infections don't work. The bacteria are not killed, and they continue to grow. When common antibiotics don't work on bacterial infections, it's known as antibiotic resistance. Antibiotic resistance makes it difficult to treat certain bacterial infections.

In the past, MRSA infections mostly happened in hospitals or nursing homes, putting people with weaker immune systems at risk. This is called hospital-associated MRSA (HA-MRSA). But now, MRSA is becoming more common in healthy people. This is known as community-associated MRSA (CA-MRSA). In both cases, it's the same MRSA bacteria, but how you treat it and reduce its spread may be different.

Anyone can get MRSA. You could have MRSA and not have any signs or symptoms. MRSA is not spread through the air like a cold or flu virus, but it can live on surfaces for a long time. There are several different ways that MRSA can spread:

• Through contact with objects that are contaminated with the bacteria, such as sports or medical equipment.
• By sharing personal items that are contaminated with the bacteria, such as a towel, bedding, or a razor.
• Through close, personal contact with someone who has an infected wound. This is more likely to happen when large groups of people are close together, such as in a college dorm, locker room, prison, health care setting, or military barracks.
• By sharing contaminated needles, which can happen when people are using injectable drugs.

If it's not treated, a MRSA infection may become more serious. If the bacteria spreads to your bloodstream, it can be dangerous, and you need to get quick medical treatment. Untreated MRSA can also spread to other people.

Other names: MRSA screening, methicillin-resistant Staphylococcus aureus screening, methicillin-resistant Staphylococcus aureus culture

What are they used for?

This test is most often used to find out if you have a MRSA infection. The test may also be used to see if treatment for a MRSA infection is working.

Why do I need a MRSA test?

You may need this test if you have symptoms of a MRSA infection. Your symptoms will depend on where the infection is located.

A MRSA infection on the skin may look like a type of rash. A MRSA rash looks like red, swollen bumps on the skin. The bumps may be filled with fluid or pus. Some people may mistake a MRSA rash for a spider bite. However, unless you actually see the spider, the bumps are probably not from a spider bite. With MRSA, the infected area may also be:

• Warm to the touch
• Painful

Symptoms of a MRSA infection in the bloodstream or other parts of the body include:

• Fever
• Chills
• Headache
• MRSA rash

What happens during a MRSA test?

A health care provider will take a fluid sample from your wound, nose, blood, or urine. Steps may include the following:

Wound sample:

• A provider will use a special swab to collect a sample from the site of your wound.

Nasal swab:

• A health care professional will use a special swab to take a sample from your nose.

Blood test:

• A provider will take a sample of blood from a vein in your arm.

Urine test:

• You will provide a sterile sample of urine in a cup, as instructed by your provider.

After your test, your sample will be sent to a lab for a bacteria culture test. Most tests take 24-48 hours to get results. That's because it takes time to grow enough bacteria to be detected. There is also a molecular test, which can deliver results much faster. The test, which is done on nasal swabs, can find MRSA bacteria in as little as five hours.

Talk to your provider to see which test would be a good choice for you.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a MRSA test.

Are there any risks to the test?

There is very little risk to having a wound sample, swab, or urine test.

You may feel a little pain when a sample is taken from a wound. A nasal swab may be slightly uncomfortable. These effects are usually mild and temporary.

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

If your results are positive, it means you have a MRSA infection. Treatment will depend on how serious the infection is. For mild skin infections, your provider may clean, drain, and cover the wound. You may also get an antibiotic to put on the wound or take by mouth. Certain antibiotics still work for some MRSA infections.

For more serious cases, you may need to go to the hospital and get treated with powerful antibiotics through an IV (intravenous line).

To understand the results of a MRSA test, your provider will consider your symptoms, medical history, and the results of other tests.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about MRSA tests?

The following steps can lower your risk of getting a MRSA infection:

• Wash your hands often and thoroughly, using soap and water.
• Use alcohol-based hand sanitizer if you can't wash your hands.
• Keep cuts and scrapes clean and covered until they are fully healed.
• Don't share personal items such as towels and razors.
• Use disinfecting sprays or wipes on light switches, remote controls, or other areas that are touched frequently.

You can also take steps to reduce antibiotic-resistant infections. Antibiotic resistance happens when people don't use antibiotics in the right way. To prevent antibiotic resistance:

• Take antibiotics as prescribed, making sure to finish the medicine even after you feel better.
• Don't use antibiotics if you don't have a bacterial infection. Antibiotics don't work on viral infections.
• Don't use antibiotics prescribed for someone else.
• Don't use old or leftover antibiotics.