Clostridium difficile was isolated from 12 (20%) of 60 retail ground meat samples purchased over a 10-month period in 2005 in Canada. Eleven isolates were toxigenic, and 8 (67%) were classified as toxinotype III. The human health implications of this finding are unclear, but with the virulence of toxinotype III strains further studies are required.

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Summary Faecal samples from adult horses and from foals with diarrhoea or with normal faeces were evaluated for the presence of Clostridium difficile, C. difficile toxins, C. perfringens enterotoxin (CPE) and C. perfringens spore counts. Clostridium difficile was isolated from 7/55 horses (12.7%) and 11/31 foals (35.5%) with colitis, but from 1/255 normal adults (0.4%) and 0/47 normal foals (P<0.001). Clostridium difficile toxins A and/or B were detected in 12/55 diarrhoeic adults (21.8%) and 5/30 diarrhoeic foals (16.7%) but in only 1/83 adults (1.2%) and 0/21 foals with normal faeces (P<0.001 and P<0.05, respectively). Clostridium perfringens enterotoxin was detected in 9/47 diarrhoeic adults (19%) and 8/28 diarrhoeic foals (28.6%), but was not detected in 47 adult horses (P<0.002) or 4 foals (P = 0.22) with normal faeces. The positive predictive value of isolation of C. perfringens with respect to the presence of CPE was only 60% in adult horses and 64% in foals. There was no association between total C. perfringens spore count and CPE in the faeces. The overall mortality rate from colitis was 22% for adult horses and 18% for foals. Clostridium difficile toxin‐positive adult horses with colitis were less likely to survive than C. difficile‐negative horses with colitis (P = 0.03). This study provides further evidence that C. difficile and enterotoxigenic C. perfringens are associated with equine enterocolitis.

In this prospective study, feces of dogs with diarrhea were compared with feces of normal dogs for the presence of Clostridium difficile, C difficile toxins A and B, C perfringens, and C perfringens enterotoxin (CPE). C difficile toxins A, B, or both were present in feces of 18 of 87 (21%) dogs with diarrhea and 4 of 55 (7%) normal dogs (P 0.03), whereas CPE was present in the feces of 24 of 87 (28%) dogs with diarrhea and 3 of 55 (5%) normal dogs (P 0.01). C difficile was isolated from 2 of 87 (2%) dogs with diarrhea but was not isolated from the feces of 55 normal dogs, possibly because of poor survival of the organism in fecal samples. C perfringens was isolated from the feces of 23 of 24 (96%) CPE-positive dogs with diarrhea, 52 of 63 (83%) CPE-negative dogs with diarrhea, and 39 of 55 (71%) CPE-negative dogs with normal feces. No correlation was found between C perfringens spore number and the presence of CPE.

We previously reported Clostridium difficile in 20% of retail meat in Canada, which raised concerns about potential foodborne transmissibility. Here, we studied the genetic diversity of C. difficile in retail meats, using a broad Canadian sampling infrastructure and 3 culture methods. We found 6.1% prevalence and indications of possible seasonality (highest prevalence in winter).

Clostridium difficile is the bacterium most commonly surmised to cause antimicrobial-and hospital-associated diarrhea in developed countries worldwide, and such infections are thought to be increasing in frequency and severity. A laboratory-based study was carried out to characterize C.

Molecular typing of Clostridium difficile isolates from animals and humans may be useful for evaluation of the possibility for interspecies transmission. The objective of this study was to evaluate C. difficile isolates from domestic animals and humans using PCR ribotyping. Isolates were also tested using PCR for the presence of genes encoding toxins A and B. One hundred and thirty-three isolates of C. difficile from dogs (n = 92), horses (n = 21) and humans (n = 20), plus one each from a cat and a calf, were evaluated. Overall, 23 ribotypes were identified. Of these, nine were identified from dogs, 12 from horses, seven from humans and one each from the cat and calf. In dogs, humans and horses, one or two different ribotypes predominated. Overall, 25 % of isolates from humans were indistinguishable from isolates from one or more animal species. Genes encoding C. difficile toxins A and B were detected in all human, equine and bovine isolates, and in 69 % of canine isolates. While different ribotypes appear to predominate in different mammalian species, several indistinguishable strains may be found in multiple species. This suggests that there is a potential for interspecies transmission of C. difficile and epidemiological studies are warranted.

Although Clostridium difficile is recognized as a cause of enterocolitis in horses and humans, there has been little work published regarding the lability of C. difficile and its toxins in feces. A significant decrease in recovery of C. difficile from inoculated equine fecal samples occurred during storage. Recovery after storage in air at 4 degrees C decreased from 76% (37/49) after 24 hours to 67% (33/49) at 48 hours and 29% (14/ 49) after 72 hours. In contrast to aerobic storage, 25 of 26 samples stored anaerobically at 4 degrees C yielded growth of C. difficile for 30 days, whereas the organism was only detected for 2.5 +/- 2.52 days (x +/- SD) in paired samples stored aerobically. The use of an anaerobic transport medium was effective in maintaining viability of C. difficile. These findings indicate that poor aerotolerance is the reason for the rapid decrease in culture yield. In contrast to C. difficile organisms stored aerobically at 4 degrees C, C. difficile toxins were considerably more stable and could be detected by enzyme-linked immunosorbent assay in both broth and inoculated fecal samples for at least 30 days. The poor survival of C. difficile but the stability of its toxins when feces are stored aerobically must be considered when submitting samples for diagnosis of C. difficile-associated enterocolitis in horses and when interpreting laboratory results.