Postnatal change of pig intestinal ganglioside bound by Escherichia coli with K99 fimbriae.

Enterotoxigenic Escherichia coli possessing K99 fimbriae (E. coli K99) causes diarrhea in piglets of less than 1 week old. The first stage of the bacterial infection is adhesion by the fimbriae on the small intestinal mucosa and the adhesion is followed by colony formation. K99 fimbriae bind specifically to N-glycolylneuraminyl-lactosyl-ceramide, GM3(NeuGc) [Ono, E. et al. (1989) Infect. Immun. 57,907-911]. We examined the postnatal change of the content and the molecular species of GM3(NeuGc) in the small intestinal mucosa of 0- to 14-day-old piglets and adult pigs. GM3(NeuGc) was a major ganglioside of piglet intestinal mucosa. GM3(NeuGc) content was maximal at birth and gradually decreased to 1/16 in adult animals (5 months old). The ceramide moiety of piglet intestinal GM3(NeuGc) was characterized by the presence of 2-hydroxylated palmitic acid. 125I-labeled bacteria strongly bound to GM3(NeuGc) containing 2-hydroxylated palmitic acid and phytosphingosine compared with GM3(NeuGc) containing any other ceramide moiety. The time when this particular GM3(NeuGc) appears coincides with the time that the infection occurs, and it may explain the susceptibility of newborn piglets to E. coli K99 infection.