A prospective study of the roles of Clostridium difficile and enterotoxigenic Clostridium perfringens in equine diarrhoea

Faecal samples from adult horses and from foals with diarrhoea or with norm al faeces were evaluated for the presence of Clostridium difficile, C. diff icile toxins, C, perfringens enterotoxin (CPE) and C. perfringens spore cou nts. 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 no rmal foals (P <0.001). Clostridium difficile toxins A and/or B were detecte d in 12/55 diarrhoeic adults (21.8%) and 5/30 diarrhoeic feats (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 no t 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 r espect 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 h orses 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. diffi cile and enterotoxigenic C, perfringens are associated with equine enteroco litis.