Net fluid secretion and impaired villous function induced by colonization of the small intestine by nontoxigenic colonizing Escherichia coli

Abstract

The role of colonizing bacteria in the small bowel in causing diarrhea remains unclear. We examined whether colonizing, nontoxigenic Escherichia coli could alter small bowel function by determining net water and electrolyte fluxes and sucrase activity in colonized and noncolonized ileal segments by using the reversible-ileal-tie adult rabbit model. Colonization of the ileum with nontoxigenic E. coli for ≥72 h at ≥104/cm2 was associated with significant functional derangement, as follows: (i) overt liquid diarrhea in 50% of animals colonized at >104/cm2; (ii) reversal of normal net ileal absorption to net secretion of water, sodium, and chloride; and (iii) significant decrease in mucosal sucrase activity. We conclude that small bowel colonization by colonizing, nontoxigenic E. coli impairs water and electrolyte absorption and sucrase activity in the absence of recognized enterotoxin, cytotoxin, invasion, or effacement traits.