C. diff Infections in Hospitals Are Leveling Off

Oct. 26, 2011 (Honolulu) -- After explosive growth in North American hospitals at the beginning of the millennium, the number of new infections with the bacterium Clostridium difficile (C. diff) appears to have leveled off, a new study shows.

"We find this tremendous growth from 2000 to 2005, but from 2005 to 2009 there is a leveling off," study co-researcher Marya D. Zilberberg, MD, MPH, tells WebMD.

C. diff infection can cause severe diarrhea, most often when a patient takes antibiotics for some other purpose. The antibiotics kill the beneficial bacteria, allowing C. diff to grow out of control. Other antibiotics can be used to kill the C. diff, but the organism is evolving resistance to them.

"We used to have nice tame C. difficile bugs in the hospital," says Zilberberg, who is the CEO of the consulting firm EviMed Research Group in Goshen, Mass.

But in the 1980s and 1990s, hospitals used a lot of antibiotics in a class of drugs called fluorquinolones. Gradually, a strain of C. difficile evolved resistance to these drugs. It also evolved sticky spores that are hard to clean from hospital surfaces, allowing it to spread more easily, Zilberberg says.

"Lo and behold what we had is this new hypervirulent [increase in ability to cause disease] strain," she says. "It's a bug for the 21st century."

Analyzing data on hospital infections maintained by the U.S. Agency for Healthcare Research and Quality, Zilberberg and her colleagues found that the rate of C. diff infections in U.S. hospitals more than doubled from 2000 to 2005. Since then it has more or less held steady. The number of new infections was 328,055 in 2009, the most recent year for which the researchers could obtain data.

They reported their findings at CHEST 2011: the American College of Chest Physicians Annual Meeting.

Treating C. diff

Until recently, there was only one antibiotic, vancomycin, approved by the FDA to treat C. diff. In May, the FDA approved fidaxomicin for this purpose. (Optimer Pharmaceuticals, which makes fidaxomicin, hired Zilberberg and her colleagues to conduct this study.)

Metronidazole is sometimes used as well, even though it is not approved by the FDA for that  purpose.

But creating new antibiotics is not the best solution to fighting drug-resistant bacteria because they will keep evolving resistance to the new drugs, Zilberberg says.

She says the reason the infection rate has leveled off may be that hospitals are becoming more careful not to overuse antibiotics. They may also be doing a better job of infection control through such measures as isolating patients with infections and making sure people in the hospital wash hands.

Patients, too, can play a role in preventing the spread of this organism, which sometimes causes infections outside hospitals as well.

"What I always say to consumers is, 'Never demand an antibiotic and if your doctor offers, ask three times if it's really needed,'" Zilberberg says.

Carl D. Boethel, MD, assistant professor of internal medicine at the Texas A&M Health Science Center in College Station, agrees. "We are sort of victims of our own success," he tells WebMD.

Hospital visitors can help control the outbreak of C. diff. You should wash your hands every time you enter or leave a patient's room in the hospital, Boethel says. Use soap and water because alcohol is not effective against C. diff.

This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.