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Drug-resistant germ raises fears as it takes toll

More in US dying from its infections than from AIDS

WASHINGTON - A dangerous germ that has been spreading around the country causes more life-threatening infections than public health authorities had thought and is killing more people in the United States each year than the AIDS virus, federal health officials reported yesterday.

The microbe, a strain of a once innocuous staph bacterium that has become invulnerable to first-line antibiotics, is responsible for more than 94,000 serious infections and nearly 19,000 deaths each year, the Centers for Disease Control and Prevention calculated.

Although evidence has been mounting that the infection is becoming more common, the estimate published today in the Journal of the American Medical Association marks the first national assessment of the toll from the insidious pathogen, officials said.

"This is the first study that's been able to capture the data in a comprehensive fashion," said Scott K. Fridkin, a medical epidemiologist at the CDC. "This is a significant public health problem. We should be very worried."

Other researchers said the estimate includes only the most serious infections caused by the bug, known as methicillin-resistant staphylococcus aureus, or MRSA.

"It's really just the tip of the iceberg," said Elizabeth Bancroft, a medical epidemiologist at the Los Angeles Department of Public Health who wrote an editorial accompanying the new research. "It is astounding."

On Monday, a Lynch Station, Va., teenager, Ashton Bonds, 17, succumbed to MRSA, prompting officials to shut down 21 Bedford County schools for cleaning to prevent further infections. The infection had spread to Bonds's kidneys, liver, lungs, and the muscle around his heart.

The MRSA estimate is being published with a report that a strain of another bacterium, which causes ear infections in children, has become impervious to every approved antibiotic for youngsters.

"Taken together, what these two papers show is that we're increasingly facing antibiotic-resistant forms of these very common organisms," Bancroft said.

The reports underscore the need to develop new antibiotics and curb the unnecessary use of those already available, specialists said. The reports should also alert doctors to be on the lookout for antibiotic-resistant infections so patients can be treated with the few remaining effective drugs before they develop serious complications, specialists said.

MRSA is a strain of the ubiquitous bacterium that usually causes staph infections easily treated with common antibiotics in the penicillin family, such as methicillin and amoxicillin. Resistant strains of the organism, however, have been increasingly turning up in hospitals and in small outbreaks outside healthcare settings.

The germ, which is spread by casual contact, rapidly turns minor abscesses and other skin infections into serious health problems, including painful, disfiguring "necrotizing" abscesses that eat away tissue. The infections can often still be treated by lancing and draining sores and quickly administering other antibiotics, such as bactrim. But in some cases the microbe gets into the lungs, causing unusually serious pneumonia, or spreads into bone, vital organs, and the bloodstream, triggering life-threatening complications. Those patients must be hospitalized and given intensive care, including intravenous antibiotics such as vancomycin.

In the new study, Fridkin and his colleagues analyzed data collected in Connecticut, Georgia, California, Colorado, Oregon, New York, Tennessee, Minnesota, and Maryland, identifying 5,287 cases of invasive MRSA infection and 988 deaths in 2005. Based on the findings, the researchers calculated that MRSA was striking 31 out of every 100,000 Americans, which translates into 94,360 cases and 18,650 deaths nationwide. In comparison, the AIDS virus killed about 12,500 Americans in 2005.

"This indicates the life-threatening MRSA infection is much more common than we had thought," Fridkin said.

In fact, the estimates make MRSA much more common than flesh-eating strep infections, bacterial pneumonia, and meningitis combined, Bancroft said.

The infection is most common among African-Americans and the elderly, but also commonly strikes very young children.

Studies have shown that hospitals could do more to reduce the spread of the infection through standard hygiene measures. Individuals can reduce their risk through common-sense measures, such as frequent hand-washing.

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