Experimental Clostridium difficile enterocolitis in foals and molecular typing of C. difficile isolates originating from different species and a teaching hospital environment.

摘要

Clostridium difficile is a well-recognized enteropathogen in humans and recently also has been described in several animal species. There are a plethora of clinical cases and case series published in domestic animal species including laboratory animals. This study developed an experimental model of C. difficile induced disease in foals to substantiate Koch's postulates for infectivity in the horse.; Nine one-day-old pony foals were inoculated intragastrically with spores or vegetative cells of C. difficile strain WS-108 previously isolated from a horse with clinical colitis. Five foals were challenged orally with spores (two received 105 CFUs [colony forming units] and three, 107 CFUs intragastrically once daily for three days). To disrupt normal gastrointestinal flora, a single dose of clindamycin was administered 24 hours after the third inoculum. Four foals were challenged by oro-gastric administration of 1010 CFUs of vegetative cells once daily for three days or until diarrhea developed. This group did not receive clindamycin. Clinical signs varied from mild abdominal discomfort and pasty feces to colic and watery diarrhea in eight out of nine foals. Four of five foals challenged with spores developed mild diarrhea whereas all foals challenged with vegetative cells developed moderate to severe diarrhea. Clostridium difficile was isolated from feces of all foals between 24 to 72 hours after inoculation. Toxins A or B, or both, were detected in the feces of all foals using an ELISA test. These findings confirmed germination and toxin expression from both spores and vegetative cells in association with development of clinical signs.; In an additional study, a series of C. difficile isolates from animals with enterocolitis (dogs, horses, cat, calf), from healthy animals (dogs), from a veterinary hospital environment and from human cases of C. difficile-associated diarrhea (CDAD) were compared using molecular typing. One hundred and thirty-five isolates of C. difficile were subjected to PCR-ribotyping and toxinotyping using previously described methods. A wide diversity of ribotypes was identified, with some ribotypes predominating in different mammalian species. Several indistinguishable ribotypes were found across several species. This suggests that there is interspecies transmission of C. difficile and suggests there is a need for in-depth epidemiological studies of interspecies transmission.