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 MEER-sah), can cause serious infection because of its resistance to antibiotics.
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, the CDC says. This type of MRSA infection is classified by researchers as hospital-associated MRSA, or HA-MRSA. A MRSA infection can be deadly, and in fact, it has become a growing problem in hospitals.
Outside the hospital
Although 85 percent 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. A study published in 2007 in the Journal of the American Medical Association found that CA-MRSA is a more widespread problem than researchers had thought. Recent cases of CA-MRSA have appeared among school athletes, and several children have died.
In 2005, the year covered by the study, serious MRSA infections--in both hospitals and communities--affected an estimated number of more than 94,000 Americans. That year MRSA infections killed an estimated number of more than 18,000 people.
Some areas of the country have been harder hit by MRSA infections than others, the CDC says. The highest rates are in the South and Southwest, including Atlanta, Los Angeles, and parts of Texas. But cases have been reported in other areas, including West Virginia and Connecticut.
Who's at risk?
S. aureus is found on the skin and in the nose of up to 30 percent of Americans, the CDC says. 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.
The JAMA study also found that age, gender, and race were factors in developing serious MRSA infections. Serious--invasive--infections were higher among adults older than 65. They were also higher in males and in African Americans.
What are the symptoms?
CA-MRSA infections commonly show up as pustules or boils, which appear as red, swollen, or painful bumps, the CDC says. 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.