C. difficile thriving even without antibiotic use
■ The rate of infection is increasing, as is doctors' vigilance in testing for it.
By Susan J. Landers — Posted Oct. 27, 2008
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Washington -- A new study gives more evidence that infection with Clostridium difficile is not necessarily preceded by the use of antibiotics. This suspicion was first raised in 2005 by the Centers for Disease Control and Prevention.
Researchers at McGill University in Montreal found that more than half of the 836 patients they studied had not been exposed to antibiotics in the 45 days before their hospitalizations for C. diff. The study is in the Oct. 7 Canadian Medical Assn. Journal.
Physicians need to maintain a high level of suspicion that the microbe may be the cause of patients' severe diarrhea even without the long-recognized contributions of antibiotics, the researchers said.
The frequency of infection with community-associated C. diff is rising. The rate per 100,000 person-years among people 65 and older in Quebec rose from 0.5 in 1997 to 57.2 in 2004, the Canadian researchers found. The number of fatalities among the most vulnerable also continues to grow.
Quebec has weathered particularly large outbreaks of the infection in recent years, and nearly everyone who arrives at a hospital with diarrhea is tested for the bacteria, said the study's lead author, Sandra Dial, MD, assistant professor of medicine at McGill. "I think we have a higher index of suspicion after what we've been through."
Outbreaks also have been common in the United States. When Ohio in 2006 mandated the reporting of C. diff among nursing home and hospital patients, the tally topped 14,000.
David Classen, MD, a clinical infectious diseases specialist and associate professor of medicine at the University of Utah's School of Medicine in Salt Lake City, said that awareness of the virulent microbe was high in his practice and that physicians are testing for it.
The Canadian researchers analyzed only C. diff infections acquired outside the hospital by Quebec patients ages 65 and older.
The infections also were serious enough to require hospital admittance. Patients with hospital-acquired C. diff were excluded because of the increased risk of infection and antibiotic use in hospitals.