TOXICOLOGY AND HISTOPATHOLOGY OF THE HEAT‐STABLE ENTEROTOXIN OF YERSINIA ENTEROCOLITICA IN INFANT AND ADULT MICE

Yersinia enterocolitica heat‐stable enterotoxin (YST) was partially purified by ion exchange, gel filtration and Fast Protein Liquid chromatography. Infant mice given YST orally (p.o.) exhibited diarrhea 4 h after administration; a few infants died by 6.5 h. Pups dosed intraperitoneally (i.p.) and adults dosed p.o., i.p. and intravenously showed no symptoms during the 7 days of observations. Tissues of adult mice orally challenged with YST showed no pathological changes by light microscopy. Livers of infant mice orally dosed with YST showed evidence of severe glycogen depletion. The intestinal tracts of YST‐dosed (p.o.) infant mice exhibited severe pathological changes including: epithelial cell and villous tip necrosis, villous edema, and capillary and lacteal engorgement. Kidneys of YST‐dosed (p.o.) infant mice exhibited devacuolization of the proximal convoluted tubule cells which indicates metabolic inactivity and a probable decrease in the resorption of glomerular filtrate (protein, carbohydrate, electrolytes and water).