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Bacteria are everywhere, even on our skin--and most exist without causing any health problems. Staphylococcus aureus--or staph--is one of those common skin bacteria. Staph and other bacteria become a problem when they cause infection. An infection can develop when the bacteria enter a scratch, cut, or other wound.

Bacterial infections can be treated with antibiotics. For some types of staph bacteria, however, common antibiotics don't work because the bacteria have become resistant to them. A type of staph bacteria called methicillin-resistant staphylococcus aureus, or MRSA (pronounced MEHR-sah), can cause serious infection because of its resistance to antibiotics.

Hospital-associated MRSA 

MRSA has been a problem for more than 40 years in hospitals and nursing homes, where it can be spread as a result of inconsistent adherence to infection control protocols because of various factors. People who are sick enough to be in a hospital or nursing home are vulnerable to infections because their immune system has been weakened by illness. MRSA infections can range from mild skin infections to serious infections of the bloodstream and lungs. This type of MRSA infection is classified as hospital-associated MRSA, or HA-MRSA.

Community-associated MRSA 

Although the majority of MRSA infections develop in or after being in a health care setting, MRSA infections can also affect people who have not recently been in the hospital. This type of MRSA infection is classified as community-associated MRSA, or CA-MRSA. According to the CDC, cases of CA-MRSA are on the rise.

Who's at risk?

Staph. aureus is found on the skin and in the nose of up to 30 percent of Americans, according to the CDC. It can make you ill if the bacteria enter a wound. It doesn't have to be a major injury--a minor scratch or cut is enough to allow the bacteria to enter your body, where they can multiply. You can then spread the MRSA infection to others if the bacteria are on your skin or hands and you share objects, such as a towel or sports equipment, or clothing, such as a uniform.

CA-MRSA is more common in what the CDC calls the "five Cs." This refers to Crowding--infections are more likely in groups that spend time in close quarters; skin-to-skin Contact; Compromised skin--meaning cuts or scrapes on the skin; Contaminated items and surfaces; and lack of Cleanliness.

The CDC says that schools, dormitories, military barracks, prisons, and daycare centers are at higher risk for CA-MRSA because of the frequent sharing of equipment and close interactions.

Contact sports also pose a risk because skin cuts and bruises are common, making it easy for MRSA to enter the body. Players sweat, which also helps the bacteria move around on the skin.

What are the symptoms?

CA-MRSA infections commonly show up as pustules or boils, which appear as red, swollen, or painful bumps. Pus is often present in the boils. The pustules or boils usually appear at the site of a cut or scrape, or on areas of the body that are covered by hair. These include the back of the neck, the groin, the buttock, the armpits, and, in men, the beard area.

If you have pus-filled boils, see your health care provider to be tested for MRSA or other staph infection and to have them drained. Squeezing them yourself can spread the bacteria to other parts of your body or into your bloodstream. If you have a staph infection, your doctor will decide if antibiotics are needed.

More serious and possibly fatal conditions, such as pneumonia, bloodstream infections, or bone infections, are very rare in healthy people who get MRSA skin infections, the CDC says.

How is it treated?

Most MRSA infections are minor and go away with medical treatment. Researchers don't yet know why some infections become life-threatening. Some suspect that some of the bacteria have mutated into a more virulent form.

By definition, MRSA is resistant to methicillin, a group of antibiotics that include oxacillin, penicillin, and amoxicillin. But other antibiotics can be used. These may include trimethoprim-sulfamethoxazole, clindamycin, tetracyclines, or antibiotics that are given intravenously, such as vancomycin or teicoplanin.

How do bacteria become resistant to antibiotics? According to the FDA, these are common causes of bacterial resistance:

  • Using antibiotics for illnesses that aren't caused by bacteria. Some patients have asked their doctors for antibiotics to treat viral infections such as colds and the flu. Viral infections do not respond to antibiotics.

  • Giving antibiotics to food-producing animals, such as cattle, chickens, and pigs. These drugs are given to animals not only for health reasons, but also to increase production.

  • Failing to take antibiotics as directed. Some people stop taking an antibiotic as soon as they feel better, instead of completing the full dose.

For a MRSA skin infection, treatment usually involves draining any pus and applying an appropriate dressing. Most skin infections do not need antibiotic treatment, unless more serious symptoms develop.

Can you prevent infection?

According to the CDC, these factors increase your risk for a community-associated MRSA infection:

  • You are a child. A child's immune system isn't fully developed.

  • You participate in team contact sports.

  • You share towels or athletic equipment.

  • You live in crowded or unsanitary conditions.

  • You have an illness such as AIDS, which weakens your immune system.

The CDC offers these recommendations to help prevent MRSA infection:

  • Wash your hands frequently, using soap and water or an alcohol-based (at least 60 percent alcohol) sanitizer. This is especially important when you have been out in public, touching or using items that other people have touched or used.

  • Shower after you work out at a fitness club or gym, or after participating in sports practice or a game.

  • Cover any cut or scrape with a clean, dry bandage until it has healed.

  • Don't share towels, razors, and other personal items that come in contact with your skin.

  • When using workout machines or gym equipment, put a barrier such as a towel between you and the equipment or wipe it down.

  • Keep communal surfaces clean with disinfectant. Wash sheets, towels, and sports clothing in hot water and dry them on high heat to kill any bacteria present.

According to the CDC, your risk for a hospital-associated MRSA infection increases with these situations:

  • You are in the hospital or have been recently

  • You live in a long-term care facility

  • You have had surgery or other invasive procedure

  • You have recently used antibiotics or use them long-term

To protect yourself in a health care setting, the CDC offers these ideas:

  • Ask health care staff to wash their hands before touching you.

  • Wash your own hands.

  • Make sure medical staff uses sterile procedures when inserting and removing intravenous tubes and catheters.