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News Release

October 04, 2006

OVC Study Finds Bacterium in Dairy Calves

A bacterium that is the major cause of one of the most common hospital infections in the world has been found in Ontario food animals by researchers at the Ontario Veterinary College.

Their investigation of Clostridium difficile will be published in an upcoming issue of the journal Emerging Infectious Diseases.

Scott Weese, a University of Guelph clinical studies professor and one of the study’s authors, says the research focus was on the presence of the bacterium in the feces of dairy calves in Ontario. It was found in 11 per cent of the animals.

He cautions against drawing conclusions from the initial findings. “It’s too soon to conclude the presence of the bacterium automatically means people can become infected and develop C. difficile-associated disease through eating meat.”

Weese, who specializes in diseases that pass between animals and humans, is investigating the presence of the bacterium in meat in another study, but said the findings have yet to be published. Similar research is also being done by the U.S. Food and Drug Administration, Food Safety and Inspection Services and National Institutes of Health.

C. difficile is recognized as the major cause of colitis (inflammation of the colon) and diarrhea. The bacterium is primarily acquired in hospitals and chronic-care facilities following antibiotic therapy covering a wide variety of bacteria, and is the most frequent cause of outbreaks of diarrhea in hospitalized patients. It has caused severe hospital outbreaks in Quebec and Great Britain, and in the United States alone, it causes about three million cases a year.

But increasingly, it’s been discovered in people who haven't been hospitalized, which has fuelled suspicions about how it was contracted and whether food supply is to blame.

Weese and Alexander Rodriguez-Palacios, the study’s lead author, tested feces samples from 278 calves from 102 farms in Ontario. Rodriguez-Palacios is a D.V.Sc. student and is completing a residency in large-animal internal medicine at OVC. His research focuses on developing probiotics for prevention of diarrhea and epidemiology of infectious diseases, particularly of pathogens with potential public health implications.

They found that the cattle strains of C. difficile were “indistinguishable'” from those that have infected humans. Weese said that there could be several explanations. These include the strains evolving in parallel in different species and there being regular movement of various types of the bacterium among different species. “Further study is needed to evaluate these possibilities,” he said.