Kinetics of appearance of intestinal lesions in mice mono-associated with a lethal or non-lethal strain of Clostridium difficile

Unité de Recherche en Immunologie, Faculté de Pharmacie, Université de Montpellier 1, 34060 Montpellier Cedex 1 * Laboratoire d'Ecologie et de Physiologie du système Digestif, INRA, CRJ, 78350 Jouy-en-Josas, France Received April 19, 1993 Revision received July 4, 1993. SUMMARY: The kinetics of the appearance of intestinal lesions induced by orogastric inoculation of gnotobiotic mice with a lethal strain of Clostridium difficile (VPI) that produced toxins A and B in vivo and in vitro was studied and compared with the lesions induced by non-lethal C. difficile strain 786 that produced toxins A and B in vitro but only toxin B in measurable amounts in vivo . Different portions of the intestine were removed 12, 20,26 and 30 h after inoculation and studied by scanning electronmicroscopy. The remaining portions were homogenised for enumeration of C. difficile and quantification of toxin A by enzyme immunoassay and toxin B by cytotoxicity. The results showed that, following inoculation: (i) measurable amounts of both toxins were necessary to produce lesions; (ii) with strain VPI, the caecum and the colon were rapidly impaired and completely destroyed after 1 day, whereas the small intestine was damaged to a lesser extent; (iii) C. difficile strain 786 did not cause mucosal damage but induced mucus-like or serum-like secretion and morphological changes in the caecal enterocytes only.