Half Million Suffer Antibiotic-Related Infections, U.S. Says

About half a million Americans suffered a devastating infection related to antibiotic use in 2011, as much as double previous estimates, and 29,300 of them died, U.S. researchers said.

The bacteria Clostridium difficile has become the most common pathogen in hospitals, nursing homes and other health-care facilities and is the leading cause of deaths from intestinal infections, according to a Centers for Disease Control and Prevention study published today in the New England Journal of Medicine. The agency had previously estimated that C. difficile infects between 240,000 and 330,000 Americans annually.

The bacteria causes severe diarrhea and can lead to kidney failure and sepsis, a life-threatening inflammation from infection. Its very name, French for “difficult,” alludes to its burden on the U.S. health-care system, where it adds at least $4.8 billion in costs, the CDC said.

Use of antibiotics, which destroy normal gut bacteria, can make room for C. difficile to infect the bowels, Michael Bell, deputy director of the Division of Healthcare Quality Promotion in the National Center for Emerging and Zoonotic Infectious Diseases, said in a conference call with reporters.

“If we can improve antibiotic prescribing the number of cases of C. difficile will improve dramatically,” Bell said.

Antibiotics, which can only combat bacterial infections, are sometimes incorrectly prescribed to treat viruses. Promotion of appropriate antibiotic use in England decreased C. difficile rates there by 60 percent over three years, Bell said. Infections by the bacteria have declined in the U.S. by about 10 percent since 2011, the CDC estimates.

Of about 29,300 deaths following C. difficile infection in 2011, half were attributed to the germ, the CDC estimated. In 2007, C. difficile was estimated to cause 14,000 deaths.

Severe Strain

In the last 15 years a severe strain of the bacteria has emerged that more easily spreads. About 30 percent of people in the CDC study had the more dangerous strain, L. Clifford McDonald, an agency researcher who assisted in the work, said on the call.

Previous estimates of the bacteria’s incidence were based on reports from hospitals, nursing homes and other health-care facilities. In 2011, the CDC collected C. difficile data from diagnostic laboratories in 34 counties in the U.S. to produce the new estimates. Improved testing may have also led to the detection of more cases.

The CDC estimates 24 percent of C. difficile cases occurred in hospitals. Women, white people and those 65 or older were more likely to come down with the infection.

Antibiotics to treat C. difficile include vancomycin and Merck & Co.’s Dificid. Any antibiotic can destroy bacteria in the bowels and C. difficile patients often relapse because they can’t return their intestinal flora to normal.

Merck and Actelion Ltd. are among companies working on new drugs to treat C. difficile. Sanofi is developing a vaccine against the infection.

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