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C. Difficile Found in Meat
OVC prof cautions against drawing premature conclusions
BY LORI BONA HUNT
Two researchers in the Department of Clinical Studies who earlier this month found a dangerous bacterium in food animals now have evidence that Clostridium difficile is in ground and processed meats sold in Canada.
D.V.Sc. student Alex Rodriguez-Palacios presented preliminary findings from the meat study last week at the World Buiatrics Congress in France, but co-author Prof. Scott Weese is cautioning people against drawing premature conclusions.
“It's too soon to conclude that the presence of the bacterium in meat automatically means people can become infected and develop C. difficile-associated disease through eating meat,” he says. “Finding this bacterium in meat is an important step in trying to determine whether C. difficile is a food-borne pathogen, but much more work is required to see whether there is any real risk.”
About 18 per cent of meat tested in Ontario contained the bacterium. A separate independent study by researchers at the University of Arizona found C. difficile in about 30 per cent of meat they tested. Similar research is being done by the U.S. Food and Drug Administration, Food Safety and Inspection Services and the National Institutes of Health.
Although the U.S. researchers found the human epidemic strain, it was not found in Ontario samples, says Weese. But the majority of strains found in Ontario meat samples can cause disease in people.
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; in the United States alone, it causes about three million cases a year.
Earlier this month, Weese, who specializes in diseases that pass between animals and humans, his colleague Prof. Henry Staempfli and Rodriguez-Palacios found C. difficile in the feces of about 11 per cent of dairy calves they tested in Ontario.
They found that the cattle strains were indistinguishable from those that have infected humans. Weese says there could be several explanations for this. The strains may be evolving in parallel in different species, for example, or there may be regular movement of various types of the bacterium among different species.
“Further study is needed to evaluate these possibilities,” he says.
Their study will be published in an upcoming issue of the journal Emerging Infectious Diseases.
The follow-up research looked at ground beef and ground veal that was purchased randomly from grocery stores in Guelph and tested over a period of several months. Weese says they now plan to expand the study to include other provinces.