Respiratory epithelial carbohydrate levels of rats with gram-negative bacillary colonization.

One mechanism by which severe illness or stress might facilitate adherence and colonization of GNB to respiratory epithelium is by altering epithelial cell surface carbohydrates. To investigate this possibility we used radiolabeled lectins to quantitate carbohydrate levels on intact buccal and tracheal epithelium. A rat model of GNB colonization, in which renal infarction was performed to produce colonization, was used. Buccal and tracheal epithelial surface carbohydrate levels from normal rats and rats 48 hours after renal infarction were compared. Buccal and tracheal epithelium from the renal infarction animals had decreased amounts of sialic acid and fucose, and decreased levels of these sugars occurred at the same time that heavy oropharyngeal GNB colonization developed. Tracheas obtained from the infarcted animals bound three times more Type 1 piliated GNB than normal tracheas. Sialic acid and fucose levels are decreased early after stress, and we speculate that altered epithelial carbohydrates may predispose to GNB colonization by exposing binding sites for GNB.