Methicillin-resistant Staphylococcus aureus (MRSA) infections are the top cause of skin and soft tissue infections among people in hospitals and can result in severe and even fatal disease. In fact, MRSA infections account for almost 19,000 deaths and more than 94,000 life-threatening illnesses each year in the United States.
"Invasive MRSA is an important public health problem," said lead researcher Dr. R. Monina Klevens, an epidemiologist at the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta. "We need to do a better job in preventing MRSA infections," she added.
In the study, Klevens' group used data from the Active Bacterial Core surveillance/Emerging Infections Program Network from July 2004 through December 2005 to estimate the incidence of MRSA infection in the United States.
The report is published in the Oct. 17 issue of the Journal of the American Medical Association.
The researchers uncovered 8,987 cases of invasive MRSA. Most of these (58.4 percent) were found in community health care settings, 26.6 percent were in hospitals, 13.7 percent were infections not associated with health care facilities and 1.3 percent could not be classified.
Klevens' team estimated the rate of invasive MRSA in 2005 at 31.8 per 100,000 persons, but that rate was higher for certain populations.
By age, rates of infection were highest for those 65 and older (almost 128 cases per 100,000). Blacks were much more likely than whites to become infected, at 66.5 cases per 100,000 versus about 28 per 100,000, respectively. Men had more cases (37.5 per 100,000) than women (26.3 per 100,000). The lowest rate was for children 5 to 17 years of age, at 1.4 cases per 100,000.
Based on these data, the researchers estimated that there were 94,360 cases of invasive MRSA in the United States in 2005, and 18,650 deaths caused by these infections.
Klevens believes more effort is needed, especially among health care providers, to reduce the number of infections. "This is really a call for action to health care settings that we need to do a better job at preventing MRSA," she said.
One expert agreed that the new study should serve as a warning.
"This is really the first study to quantify how much MRSA is occurring in the United States," said Dr. Elizabeth A. Bancroft, an epidemiologist at the Los Angeles County Department of Public Health and author of an accompanying journal editorial. "The rate of infection is a lot higher than what was expected," she added.
The rate of MRSA is higher than the rate of the four other invasive bacterial diseases that public health officials typically study, Bancroft said. In fact, more people died in 2005 from MRSA infections in the United States than died from AIDS, she noted.
"The MRSA rate is only the tip of the iceberg, because this study only included cases that are invasive," she said. "MRSA, especially in the community setting, is more likely to cause skin infections," she said.
Prevention is relatively simple: People can protect themselves from MRSA by washing their hands, keeping wounds covered and maintaining good hygiene, Bancroft said. "You don't always need antibiotics to treat this infection," she said. "A lot of times, it can be treated by having a doctor drain the pus out."
"The most common way MRSA is spread is from person-to-person," Bancroft said.
In the hospital or other health care facilities, patients should make sure that doctors and nurses wash their hands before touching them, starting an IV or inserting a catheter or other invasive device, Bancroft said.
MRSA in the outside community is most often passed from one person to another through casual contact, such as body contact during sports, sharing towels or athletic equipment, particularly in schools and prisons, Bancroft said.
Outbreaks of staph skin infections are being reported this year in schools across America, and some of them are caused by MRSA, the Associated Press reported on Saturday. Most infections are being spread in school gyms and locker rooms as athletes with minor cuts and abrasions share equipment, experts said.
"Most of these are mild infections," Nicole Coffin, spokeswoman at the U.S. Centers for Disease Control and Prevention, told the AP. "They can be as simple as a pimple or a boil, or as serious as a blood infection."
In a Newport News, Va., high school, four students were infected with staph, one of them carrying the MRSA strain. That patient, a football player, was briefly hospitalized this week, the AP said.
Other outbreaks of a similar nature have occurred in schools in Illinois, Maryland, New York, Ohio, Pennsylvania, and South Carolina, the AP added.
