Investigation of Clostridium difficile as an enteropathogen in dogs and cats
This thesis presents the results of investigations into the role of Clostridium difficile as an enteropathogen in cats and dogs. The objectives of the study were to determine the prevalence of Clostridium difficile intestinal colonization in dogs and cats hospitalized in an intensive care unit (ICU) and to assess risk factors that influence intestinal carriage. Another objective of this study was to develop a canine model of Clostridium difficile-associated disease (CDAD) by inoculating 6 healthy dogs with vegetative cells or spores followed by the characterization of clinical signs, C. difficile fecal culture and fecal toxin A/B detection.;Clostridium difficile was isolated from 71/402 (18%) patients in the intensive care unit; 49/71 (69%) were carriers of strains that were toxigenic in vitro. Twenty-seven of 71 (38%) patients acquired or expressed C. difficile intestinal colonization during hospitalization while 37/71 (52%) were carriers upon admission. Statistically significant risk factors for intestinal carriage of C. difficile included length of hospital stay (p = 0.0018) and antibiotic administration prior to admission to ICU in combination with no antibiotic administration in ICU (p = 0.044).;Clostridium difficile-associated disease did not develop following inoculation of 6 healthy dogs with high doses of C. difficile spores or vegetative cells. No dogs developed diarrhea or other abnormal clinical signs and C. difficile toxins A, B, or both were not detected in the feces of any dog. Clostridium difficile was recovered from the feces of two dogs, both of which had received vegetative cells, on day 3 and day 3, 4, and 5 post-inoculation, respectively.;As shown in this study Clostridium difficile does colonize the intestinal tract of hospitalized dogs and cats; however, the association with the development of CDAD is still unclear. The inability to induce CDAD with high doses of vegetative cells or spores is further evidence that host factors, in addition to microbial factors, play an important role in disease development. This study reiterates the need for further research investigating the role of C. difficile as an enteropathogen in dogs and cats.