Adhesion of K99 fimbriated Escherichia coli to pig intestinal epithelium: correlation of adhesive and non-adhesive phenotypes with the sialoglycolipid content.

Evidence for the existence of two phenotypes of piglets born to experimental herds was obtained based on the susceptibility of intestinal brush borders to adhesion of K99-positive Escherichia coli. The enterocytes of the K99-receptive piglets displayed a characteristic sialoglycolipid pattern, with a higher content of the monosialoglycolipids II3NeuGc-LacCer (GM3Gc), IV3NeuGc-nLcOse4Cer (SPGGc) and IV3NeuAc-nLcOse4Cer (SPG) and the oligosialogangliosides IV3NeuAc,II3NeuAc-GgOse4Cer (GD1a), II3(NeuAc)2-GgOse3Cer (GD2), II3(NeuAc)2-GgOse4Cer (GD1b) and IV3NeuAc,II3(NeuAc)2-GgOse4Cer (GT1b) when compared to the gangliosides of non-receptive piglets. The gangliosides from enterocytes of the non-receptive piglets were mainly the monosialogangliosides II3NeuAc-GgOse3Cer (GM2) and II3NeuAc-LacCer (GM3), only traces of the other sialoglycolipids being detected. Adhesion of 14C-labelled K99-positive E. coli cells to the piglet small intestinal sialoglycolipids, as tested by the thin-layer chromatogram overlay assay, revealed that the receptive enterocyte membrane was richer in glycolipids containing K99 receptor structures than the non-receptive enterocyte. Adhesion of K99-positive E. coli correlated with the degree of sialylation of the brush border glycolipids.