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Staph Infections Turning Up Outside Hospitals

Strains starting to emerge in communities, new research reveals

WEDNESDAY, April 6, 2005 (HealthDay News) -- Staph infections that are resistant to common antibiotics are moving out of the hospital into the community.

Not only are these infections appearing in the community, they are also originating there, according to two studies appearing in the April 7 issue of the New England Journal of Medicine.

"These strains that are in the community now look like they arose there. They're not just spilling out from hospitals," said Dr. Henry Chambers, author of an editorial which accompanies the studies and the chief of infectious diseases at San Francisco General Hospital. "Before, physicians could assume it would be drug-susceptible. Now you can no longer assume that."

Staphylococcus aureus are bacteria found frequently on the skin or nose of healthy people. Occasionally, the bacteria cause infections, especially skin infections of varying degrees of severity.

Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to methicillin and other members of the beta-lactam class of antibiotics such as penicillin, oxacillin and amoxicillin.

These infections most commonly break out among patients in hospitals. Increasingly, however, staph infections and resistant staph infections are occurring in communities.

To get a better grasp on the scope of the problem, the authors of the first study analyzed medical records and interviewed people in Baltimore, Atlanta and Minnesota who had developed staph infections outside of a hospital setting.

"The main hypothesis we wanted to test was whether MRSA emerged in the community independently or had leaked out of the healthcare system," said Dr. Scott Fridkin, lead author of the study and a medical epidemiologist at the National Center for infectious Diseases, part of the Centers for Disease Control and Prevention in Atlanta.

"We now know that MRSA has emerged in the community," he added. "Eight to 20 percent of all MRSA in the three communities was community associated and not hospital associated."

Doctors need to be aware that any staph infections they are seeing may be resistant to the first-line antibiotic treatments, the authors stated.

"It's really sort of an awakening call that physicians need to think of MRSA," Fridkin said. "They used to think about it only in hospitalized persons."

The second study looked at necrotizing fasciitis or "flesh-eating disease," a life-threatening condition. Although this is not usually caused by this particular bacteria, experts recently have noted an increase in the number of infections caused by MRSA.

The study authors reviewed the records of 843 patients with MRSA at Harbor-UCLA Medical Center between January 15, 2003 and April 15, 2004. Fourteen among this group had been in the community when their infections developed.

Although none of the patients died, all had serious complications and required hospital stays.

The low mortality rate was surprising, the authors stated, given that the typical mortality rate of necrotizing fascitis is about 33 percent. It is possible that necrotizing fasciitis caused by community-associated MRSA may be less aggressive than other pathogens.

On the other hand, the authors noted, the infection spread very rapidly and it's hard to tell it apart.

"These strains represent a type of antibiotics resistant strain that has been known to occur in hospitals for over 40 years and it was felt that their ability to make it in the community was compromised by the fact that they were drug resistant and required a lot of antibiotic pressure to favor persistence," Chambers explained.

"Somehow, they have acquired whatever fitness is necessary to no longer need constant antibiotic selective pressure and they are now effective pathogens in the community as well," he added.

"You have to factor it in," he said.

There are things that the average person can do as well, said Dr. Philip Tierno director of clinical microbiology and immunology at New York University Medical Center and author of The Secret Life of Germs and Protect Yourself Against Bioterrorism.

"Whenever you have a wound site, abrasion, cut or lesion on the skin, use an antiseptic as well as a bandage to treat it," he instructed. "Don't leave it be. You could be setting the stage for a rapidly progressive infection."

Also, handwashing is critical especially if you are engaged in a contact sport such as football or in any activities that involve being in close quarters with others. "When water is not available, alcoholic gels can be beneficial," Tierno said. "An effective wash is about a teaspoon and keep it on while you sing 'Happy Birthday' twice." And bear in mind that community-acquired MRSA more often develops in young people.

Finally, avoid sharing any personal items including sports equipment. And, if you do develop an infection, see your doctor pronto.

More information

For more on community-associated MRSA, visit the CDC.

SOURCES: Scott K. Fridkin, M.D., medical epidemiologist, National Center for Infectious Diseases, U.S. Centers for Disease Control and Prevention, Atlanta; Henry F. Chambers, M.D., chief of infectious diseases, San Francisco General Hospital, and professor of medicine, University of California, San Francisco; Philip Tierno, M.D., Ph.D., director, clinical microbiology and immunology, New York University Medical Center, New York City, and author, The Secret Life of Germs and Protect Yourself Against Bioterrorism; April 7, 2005, New England Journal of Medicine
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