Clostridium difficile: a new zoonotic agent?

Clostridium difficile is mainly considered a nosocomial pathogen associated with diarrhea and pseudomembranous colitis in hospitalized patients. Austrian hospitals reported 2761 cases of C. difficile infection (including 277 lethal outcomes) in 2007, compared with 777 cases (including 54 lethal outcomes) in 2003. The occurrence of community-acquired C. difficile infection is also increasingly reported. Recent studies have shown the occurrence of C. difficile in food and animals. The aim of the present study was to determine the occurrence of C. difficile in food and animals in Austria. Between March and July 2008, gut or fecal samples from 67 cows, 61 pigs and 59 broiler chickens were collected at Austrian abattoirs. Between February and April 2008 meat samples (51 beef [25 ground], 27 pork [17 ground] and 6 samples of chicken meat) were purchased at retail outlets. Of the 187 samples tested, eight yielded C. difficile: in cows 3/67 samples (4.5%) were positive, in pigs 2/61 (3.3%), in broiler chickens 3/59 (5%). Six of the eight isolates yielded toxigenic C. difficile (toxins A and B): 2/67 (3%) cow samples, 2/61 (3.3%) pig samples, 2/59 (3.4%) chicken samples. Genes for the binary toxin were detected in one of the two pig isolates, a PCR ribotype 126 strain. None of the 84 meat samples yielded C. difficile. The results of this Austrian study suggest that animal reservoirs are possible sources, via food, of human C. difficile infection.