COLONIC STRUCTURAL AND ION-TRANSPORT ABNORMALITIES IN SUCKLING RABBITS INFECTED WITH ESCHERICHIA-COLI K12

Background: Escherichia coli K12 is a laboratory strain considered non pathogenic. The purpose of this study was to examine the effect of E. coli K12 infection on colonic structure and function. Methods: Sucklin g rabbits were infected at 10 days of age with 6 x 10(9) CFU E. coil b y intragastric inoculation and were examined 4 to 5 days later. Segmen ts of ileum and proximal and distal colon were removed for light and e lectron microscopy, and NaCl transport was examined in vitro under sho rt-circuited conditions in Ussing chambers. Results: Infection did not cause weight loss or diarrhea. Colonic mucosa was inflamed with infil tration by polymorphonuclear neutrophils mainly in the lamina propria. The proximal and distal colon exhibited reduced Na+ absorption. The p roximal colon also showed increased Cl- secretion; the ileum was unaff ected.Conclusions: Infection with E. coli K12 disrupts the epithelium and alters ion transport in the colon, probably as a result of mucosal inflammation. The changes indicate that nonpathogenic E. coli have th e potential to cause intestinal disease. (C) 1997 Lippincott-Raven Pub lishers.