The effect of postnatal age on the adherence of Shigella flexneri, Escherichia coli 0124, and E. coli 0128 to guinea pig intestinal cells.

Since postnatal development of the gastrointestinal tract has an important effect on its microbial flora and may influence the types of intestinal infections, we examined the effect of age on bacterial adherence to intestinal epithelial cells. Radiolabeled bacteria were incubated with guinea pig enterocytes released by treating loops of the intestine with solutions containing EDTA, dithiothreitol, and citrate. Nonbound bacteria were separated from intestinal cells by sedimentation on a Percoll gradient. The colonic cells avidly bound Shigella flexneri (64 bacteria per cell), Escherichia coli 0124 (59), and E. coli 0128 (53). The adherence process was Ca2+ and temperature dependent, was inhibited by fucose, glucose, and mannose, and was shown to be mediated by a carbohydrate-binding protein (lectin) on the colonic cells. Adherence of these bacteria to intestinal cells of newborn animals was only 15-25% of the adherence to adult animal cells and increased gradually, reaching adult values at about 2 weeks of age. The lectin activity, which was determined by agglutination of bacteria, was secreted with the colonic mucus. It was undetectable in the newborn animal, appeared gradually with age, and its titer correlated with the adherent capability of the colonic cells. E. coli 0128 was the only one of the bacteria tested which significantly adhered to the ileum (19 bacteria per cell) in a process inhibited by mannose. This adherence was mediated by a mannose-sensitive lectin in the bacterial pili, and not on the intestinal cells. The postnatal age had no effect on the adherence to the ileum; the newborn animal had the same adherence capability as the adult one.(ABSTRACT TRUNCATED AT 250 WORDS)