C. Diff: New Threat From Old Bug

Oct. 12, 2006 -- The ongoing epidemic of severe C. diff diarrheal disease -- driven by a 20-fold more toxic mutant strain of the bacteria -- is fast getting worse.

C. diff is shorthand for Clostridium difficile. About 3% of the population carries the bug without knowing it. Normal gut bacteria usually keep C. diff in check. Many antibiotics that kill normal bacteria don't kill C. diff. That lets it take over the gut during or after antibiotic treatment.

Spread by spores that can live for months on dry surfaces, the bug makes a toxin that poisons the intestine. Disease ranges from mild diarrhea to life-threatening colon infection with profuse diarrhea.

Once mostly confined to elderly, hospitalized patients, a bad new strain of the bug is attacking healthy, young people outside the hospital. The full extent of this community spread of C. diff isn't yet known. But it's a growing problem, says CDC medical epidemiologist L. Clifford McDonald, MD.

"We have seen this bacteria in people not usually infected with it," McDonald tells WebMD. "We see generally healthy, young people who had not been in the hospital coming down with severe C. diff disease."

McDonald's CDC team made one of several reports on the alarming C. diff epidemic at this week's annual meeting of the Infectious Diseases Society of America (IDSA), held Oct. 12-15 in Toronto, Ontario.

Nasty New <em>C. Diff</em> Bug

It's not yet clear what is behind the new epidemic of C. diff disease. There are several factors:

• The bug is becoming resistant to the most commonly used antibiotics.
• A kind of heartburn drug called a proton-pump inhibitor -- including Aciphex, Prevacid, Nexium, Prilosec, and Protonix -- appears linked to C. diff infections.
• A bad new strain of C. diff is spreading across the globe.

It's that bad new bug that most worries Fred Arthur Zar, MD, medical director at the University of Illinois Hospital and professor of medicine at the University of Illinois at Chicago.

"The new strain of C. diff has become the most predominant strain," Zar tells WebMD. "The reason it is more nasty is it mutated and figured out a way to make 20-fold more toxin than the normal strain. ... If you have it, you get sick, and you need medical attention."

In addition to making about 20 times more of the two toxins produced by normal C. diff, the new strain makes a new, third toxin similar to a toxin seen in other disease-causing bacteria.

According to the CDC, the new strain of C. diff already has invaded at least 19 U.S. states: California, Connecticut, Florida, Georgia, Illinois, Maine, Maryland, Massachusetts, Missouri, New Jersey, New York, North Carolina, Ohio, Oregon, Pennsylvania, Tennessee, Texas, Washington, and Wisconsin.

It has spread throughout Canada and, according to McDonald, is "wreaking havoc" in England, the Netherlands, Belgium, and France.