Community-Acquired Staph Infections Pose Growing Threat

Many Americans carry the germ that is becoming resistant to antibiotics

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By Meryl Hyman Harris
HealthDay Reporter

MONDAY, March 6, 2006 (HealthDay News) -- While bird flu's potential grabs the headlines, a health threat of another kind is already here in the form of staphylococcus aureus, bacteria once primarily limited to hospitals but now present in the community, new research shows.

One study focused on methicillin-resistant Staphylococcus aureus (MRSA), a bacteria that lives uneventfully in the nose of many people but sometimes leads to serious infection. Symptoms can range from something as benign as an infected paper cut, to bloodstream infections, to infections of heart valves that can be fatal, said study author Dr. Philip L. Graham III, of Columbia University and New York-Presbyterian Medical Center, in New York City.

Although the version of Staphylococcus aureus that causes pneumonia in hospitals is generally resistant to antibiotics, the version found in communities can be treated, he added.

The goal of the research, which appears in the March 7 issue of Annals of Internal Medicine, is to alert doctors to treat infections with the proper medication immediately, Graham said.

He and his fellow researchers looked at 2001-2002 data from the most recent National Health and Nutrition Examination Survey and extrapolated that about one-third of the U.S. population carries Staphylococcus aureus. But two million Americans -- fewer than 1 percent -- carry the variety that is resistant to methicillin and other members of the class of antibiotics that includes penicillin, oxacillin and amoxicillin.

For the second study in the journal, researchers examined 384 people in the Atlanta area who had S. aureus skin or soft-tissue infections and found that 72 percent had become infected outside a hospital setting. Most doctors didn't recognize the source of the infection, and recommended ineffective treatments, the researchers said.

"We were interested because, in various places people have been publishing cases, especially [involving] children, having disease caused by staph that is resistant to more antibiotics than one would expect," said Graham. As far back as 1999, four children died of the disease in Minnesota.

"There are some emergency departments of pediatrics where 70 percent of all their staff infections are community acquired. That's a large percentage. We believed that the numbers were smaller on a nationwide basis," he said.

Last month, researchers announced that genes responsible for the virulence of MRSA in the United States appear to come from another, less toxic, bacterium than the hospital version.

The problem will be here for some time to come, said Dr. Pascal James Imperato, chairman of the department of preventive medicine and community health at the State University of New York Downstate Medical Center.

"We still don't know how prevalent this problem is in the general population because the majority who acquire skin infections don't visit their physicians, they heal on their own," he said. "Only the most severe ones get treated." And, he added, the numbers may have changed since the studies were conducted.

"But those data are at least very helpful because they tell us roughly what the situation was at that point in time. They give us a baseline," he said.

Generally, those most susceptible to staph infections include people with pre-existing diseases of the skin or mucous membranes, persons with foreign objects -- such as heart valves -- in their body, and people with immunodeficiencies or chronic diseases, he said.

Imperato said the infection frequently starts with a papule that "often resembles the bite of spider. It's a hard, little lump that is very red and tender and the center portion looks like it is caving in and disintegrating." Any skin disturbances that don't appear to get better should be seen by a doctor, he said.

Though the number of cases of staph infection outside hospitals appears to be growing, there is more study to be done, and the disease is treatable. A well-informed medical community, and individual vigilance, will go far, he said.

More information

For more on community-associated MRSA, visit the U.S. Centers for Disease Control and Prevention.

SOURCES: Philip L. Graham III, M.D., department of pediatrics, Columbia University, New York City; Pascal James Imperato, M.D., distinguished service professor and chair, department of preventive medicine and community health, and director, master of public health program, State University of New York Downstate Medical Center, New York City; March 7, 2006, Annals of Internal Medicine

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