[The occurrence of Clostridium difficile in fecal samples of dogs and cats]

Fecal samples of 150 dogs and 175 cats originating from different veterinary practices were investigated for assessing the occurrence of Clostridium (Cl.) difficile by using a selective medium for cultural isolation. From dogs without enteric symptoms 7 (9.3%) of 75 samples were positive for Cl. difficile, with 2 strains being cytotoxic for bovine embryonic lung fibroblast cells, which could be neutralized by Cl. difficile-antitoxin. In samples of 75 dogs with enteric symptoms Cl. difficile could be isolated in 2 cases (2.7%). In cats 9 (9%) of 100 fecal samples deriving from animals without enteric symptoms contained Cl. difficile, while in 75 cats with enteric symptoms, the isolation rate was 6.7% (5 strains). Of either group only 1 Cl. difficile-strain showed cytotoxicity for tissue culture. The results of this study allow to conclude, that in contrast to the significance for man Cl. difficile is neither for dogs nor for cats an important enteric agent. However these pets can harbour and shed strains of Cl. difficile, even cytotoxigenic ones, in faeces. In view of these findings the possibility of occasional human infections by household dogs or cats needs attention and further investigation.