Medically Reviewed by Zilpah Sheikh, MD on June 06, 2024
Written by Allison Torres Burtka , WebMD Editorial ContributorMethicillin-resistant Staphylococcus aureus (MRSA) is a bacteria that causes infections in different parts of the body. It's tougher to treat than most strains of Staphylococcus aureus ( staph ) because it's resistant to some commonly used antibiotics.
Though most MRSA infections aren't serious, some can be life-threatening. Many public health experts are alarmed by the spread of tough strains of MRSA. It’s sometimes called a "s uperbug " because it's hard to treat.
The symptoms of a MRSA infection depend on where the infection is. MRSA often gets into a skin injury such as a cut, scrape, or burn. It also might infect a surgical wound.
What does MRSA look like?
MRSA most often appears as a skin infection, such as a boil or abscess (a mass that is full of pus). At first, it might look like a pimple, but it can turn into a hard, painful lump that is red and filled with pus. Many people who have a staph skin infection often mistake it for a spider bite.
An infection also might look like a skin lesion, or an area of skin that’s different from the rest of your skin, like a sore. If there are red streaks branching out from the lesion, that may be a sign that the infection is spreading to your bloodstream.
The area around the infection may look:
Other MRSA symptoms
The infected area may feel painful and warm to the touch. If it’s a skin injury, such as a cut, it may hurt more than a typical skin injury would.
MRSA can cause many other symptoms because it can get into your bloodstream and then settle elsewhere in the body. Along with pain at the site of the infection, the symptoms may include:
If staph infects your lungs and causes pneumonia, you may have:
MRSA can also cause an abscess in your spleen, kidney, or spine. It can cause endocarditis (heart valve infections), osteomyelitis (bone infections), joint infections, mastitis (infection in the breast), and infections of implanted prosthetic devices (such as those used in a knee replacement, for instance).
Very rarely, staph can result in necrotizing fasciitis , or "flesh-eating" bacterial infections. These are serious skin infections that spread quickly. While frightening, very few necrotizing fasciitis cases have been reported.
Garden-variety staph bacteria are common and can live in our bodies. Plenty of healthy people carry staph without being infected by it. In fact, one-third of the population has staph bacteria in their noses.
But staph can be a problem if it manages to get into the body, often through a cut. Staph is one of the most common causes of skin infections in the U.S. Usually, these are minor and don't need special treatment. Less often, staph can cause serious problems such as infected wounds or pneumonia .
Did You Know?About 2% of people (2 in 100) are MRSA carriers, even though most of them aren't infected.
Staph can usually be treated with antibiotics. But over the decades, some strains of staph, such as MRSA, have become resistant to antibiotics that once destroyed them. MRSA was discovered in 1961. It's now resistant to penicillins such as amoxicillin, methicillin, oxacillin, penicillin, and other common antibiotics known as cephalosporins.
The overuse and misuse of antibiotics have caused MRSA and other bacteria to become resistant to antibiotics. For example, people sometimes take antibiotics when they have a cold or another virus, even though antibiotics won’t help in those cases.
Antibiotics are a type of antimicrobial, or a substance used to kill microbes, including bacteria. Increased use of antimicrobials in humans, animals, and agriculture is contributing to drug resistance.
While some antibiotics still work against MRSA, this type of bacteria is constantly adapting. Researchers developing new antibiotics are having a tough time keeping up.
MRSA is contagious and spreads through contact. You can get MRSA by touching another person who has it on their skin, or by touching things that have the bacteria on them. MRSA is carried by about 2% of the population (or 2 in 100 people), although most of them don’t develop serious infections. People can carry the bacteria without having any symptoms, so they can spread it to others without knowing it.
In health care facilities, MRSA can spread through contact with an infected wound or with contaminated hands. Infections sometimes spread when patients have invasive procedures such as surgeries.
Another type of staph, MSSA (methicillin-susceptible Staphylococcus aureus ), is very common. The main difference between MSSA and MRSA is that MSSA is much less resistant to the antibiotics most doctors will give you. MSSA can be treated with penicillin and other antibiotics that don’t work on MRSA.
MSSA can cause skin infections, and if it gets into the body, it can cause pneumonia and bloodstream infections.
MRSA infections are common among people with weak immune systems, including people in hospitals, nursing homes, and other health care facilities. This is called health care-associated MRSA (HA-MRSA).
Risk factors for HA-MRSA include:
Infections can appear around surgical wounds and invasive devices, such as catheters and implanted feeding tubes.
The Department of Health and Human Services reviews the National Action Plan to Prevent Health Care-Associated Infections regularly. Some studies suggest that implementing existing prevention practices can lead to up to a 70% reduction in certain infections.
But you can get MRSA outside of health care facilities, too.
MRSA also shows up in healthy people who have not been hospitalized. This type of MRSA is called community-associated MRSA, or CA-MRSA.
CA-MRSA skin infection have spread among people who share close quarters or have more skin-to-skin contact. Examples are team athletes, military recruits, prison inmates, and children in day care.
Your risk of CA-MRSA is higher if you:
More CA-MRSA infections are being seen in the general community, especially in certain geographic regions. Most cases of CA-MRSA are mild skin infections, but sometimes they can be severe.
CA-MRSA is more likely to affect younger people than HA-MRSA is.
Testing to find out whether you have MRSA will vary depending on where the infection site is. To diagnose the problem, your doctor may take samples from different parts of your body. They may take samples of your:
Then, your doctor will send the samples to a lab to be tested for signs of drug-resistant bacteria.
The treatment that you need depends on what kind of infection you have and where it is. For example, it may be limited to a skin infection, or the bacteria may have entered your bloodstream.
Treatment may include:
If you have only a skin infection, you might not need any antibiotics. But it’s important that you don’t try to drain the abscess yourself because you can make the infection worse. Be sure to get treatment from a health care provider.
While MRSA skin infections can usually be treated in your doctor's office, severe infections will land you in the hospital. You’ll get antibiotics through an IV to help kill the infection.
Although strands of HA-MRSA and CA-MRSA come from the same bacterium, Staphylococcus aureus , they have different levels of resistance and virulence — the ability to infect and cause disease. HA-MRSA is resistant to more types of antibiotics than CA-MRSA is.
One study found that certain antibiotics may work better to treat either CA-MRSA or HA-MRSA. So, your doctor may prescribe different antibiotics based on whether you have HA-MRSA or CA-MRSA.
Can methicillin drugs treat MRSA?
Methicillin can’t treat MRSA because MRSA is resistant to it. Some other types of antibiotics can be used to treat an infection, though. Some antibiotics are more likely to treat your infection than others, depending on what type you have.
In most cases, MRSA is easily treated. But MRSA infections can be serious, so make sure you get medical care. You should call your doctor if you notice signs of active infection — most likely of the skin — with a spreading, painful, red abscess or rash . If you see red streaks coming out from the infection site, see a doctor right away because it might mean the infection is spreading to your bloodstream.
If you are already being treated for an infection, watch for signs that your medicine isn't working. Those may include:
People who are sick or have weak immune systems have a higher risk of getting serious MRSA infections. If you have a condition that lowers your immunity and think that you might have an infection, call your doctor right away.
Usually, MRSA causes mild skin infections, but sometimes, infections can become serious and more difficult to treat. If the infection spreads to your bloodstream and causes a heart infection or sepsis , for example, it can be fatal.
This is why you should see a doctor if you think you might have a MRSA infection, even if it seems superficial. That way, you can get the right treatment and make sure the infection doesn’t get any worse or spread to other parts of your body.
MRSA can live on surfaces such as furniture and towels for hours or even weeks, so any infected person can pass it to others if they touch these surfaces.
If you have a MRSA infection, good hygiene is important to avoid spreading it. This includes washing your hands and bathing or showering regularly.
Here are some tips to prevent spreading a MRSA infection:
Pets can also have MRSA and pass it on to humans. Your pet may have an active infection or be a carrier. If you think your pet has MRSA, you can get them tested at the vet and treated if needed.
MRSA is an infection that is often mild and limited to a skin infection. But in some cases, it can spread to other areas of your body and cause serious medical problems, so it’s important to see a doctor if you think you have a MRSA infection.
Although MRSA can’t be treated with some common antibiotics because it’s resistant to them, it can be treated with certain types of antibiotics. Good hygiene practices, such as frequent handwashing, can help prevent the spread of MRSA.
How do you get MRSA?
MRSA is spread through contact, including skin-to-skin contact, and by touching surfaces that have the bacteria on them.
Once you have MRSA, do you always have it?
Maybe. Sometimes MRSA goes away after treatment, but sometimes it can come back often.
What are the first signs of MRSA?
The first signs of MRSA are usually skin infections, such as a boil or abscess.
What is MRSA caused by?
MRSA is a bacteria that has become resistant to some common antibiotics. It can cause infection that can spread from one person to another.
What are the top four staph infection symptoms?
Staph infection symptoms can vary depending on the type of staph, but they may include skin infections (such as boils), pneumonia symptoms (such as a high fever and chills), signs of bone infection (such as pain and swelling), and signs of endocarditis (flu-like symptoms).
Can Staphylococcus aureu s infection be cured?
Staph infections can be treated and cured, but sometimes, infections can come back.
What are five ways a person can catch MRSA?
You can catch MRSA in a health care setting, such as a hospital, through an invasive device such as a catheter, or when someone with contaminated hands touches you. Outside of a health care setting, you can get MRSA if you share towels with someone who’s infected, you play contact sports and get infected through a cut, or you touch a contaminated surface at a day care facility, for example.
