Hypervirulent C. difficile in your grocer's freezer.
Ribotype 078, which causes diarrhea in piglets, has already been shown to be an important cause of human community acquired C. difficile--associated disease (CDAD) in the Netherlands. And two recent studies conducted in the United States and Canada found ribotype 078 in a wide variety of retail meat products in grocery stores, suggesting a possible route of animal-to-human transmission.
"We don't yet have Koch's postulates fulfilled for this idea that C. difficile is in the commercial meat supply and causes disease in humans. What we have thus far is suggestive only--not proof--but it is concerning," Dr. Mary Bessesen said at a conference on internal medicine sponsored by the University of Colorado.
In one recent study, investigators at the University of Arizona, Tucson, and the Centers for Disease Control and Prevention found C. difficile in 42% of 88 tested retail meat products from supermarkets during a 3-month period. Of the positive samples, 73% contained ribotype 078 and 23% were positive for ribotype 027. Among the meats testing positive were ground beef, ham, sausages, and products labeled as requiring no additional cooking (Emerg. Infect. Dis. 2009;15:819-21).
In another study, investigators at the University of Guelph (Ont.) found evidence of seasonality for contamination of retail meats by hypervirulent strains of C. difficile over the course of a year, with the highest rates occurring during the winter months (Emerg. Infect. Dis. 2009;15:802-5).
Possible sources of the C. difficile that was found in retail meats include fecal contamination of carcasses. "I suspect that animals carry it in their gut and on their skin when they arrive at the packing house," said Dr. Bessesen, chief of infectious diseases at the Denver VA Medical Center.
Ribotype 078 functions much like the better-known ribotype 027: It has a genetic deletion that removes the sequence that would normally control toxin production.
Today, up to 20% of all CDAD in patients presenting to hospitals is community acquired. The presentation pattern and risk factors are quite different from those of the conventional hospital-acquired CDAD.
Classically, CDAD was a nosocomial infection associated with hospitalization for longer than 1 week, advanced age, and use of antibiotics, particularly clindamycin, cephalosporins, and fluoroquinolones.
In sharp contrast, community-acquired CDAD affects all age groups, including previously healthy children and peripartum women. Affected patients often have no recent antibiotic exposure.
Another important difference is that community-acquired CDAD is more likely than hospital-acquired infection to present without diarrhea. Under these circumstances, it can closely mimic acute appendicitis.
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|Title Annotation:||INFECTIOUS DISEASES|
|Publication:||Internal Medicine News|
|Date:||Sep 15, 2009|
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