Clinical, morphological, and biochemical alterations in acute intestinal Yersiniosis.

The aim of this study was to examine the intestinal response to Yersinia enterocolitica (YE) infection. Growing New Zealand white rabbits (450-800 g) were infected with 10(10) organisms of a human pathogenic strain (n = 43) or NaHCO3 for controls (n = 30) and studied 3, 6, 10, and 14 days after infection. In a separate experiment infected (n = 6) and pair-fed controls (n = 6) were studied 6 days after infection. Weight gain, excretion of YE, and diarrhea were examined daily. At sacrifice segments of proximal and mid- and distal small intestine, cecum, and colon were obtained for histologic examination and mucosa of small intestine and colon for enzyme determinations. Infection with YE resulted in weight loss and diarrhea within 48-72 h. Microabscesses were present in all sections of small and large intestine by day 3 but became more severe in the ileocecal region by day 6. In infected animals at day 6 there was crypt hyperplasia throughout the small intestine and villus atrophy in the ileum. Disaccharidases were decreased in all regions by day 3 but returned to normal by day 14 in proximal and mid-, but not distal, small intestine. The pair-fed controls experienced a similar weight loss to infected animals, but showed only minor morphologic changes and no mucosal enzyme abnormalities. Our findings demonstrate that infection of weanling rabbits with YE causes diarrhea and weight loss and that, while the weight loss is largely due to reduced food intake, the morphologic and mucosal enzyme alterations are due to intestinal injury by the organism.