Colonic structural and ion transport abnormalities in suckling rabbits infected with Escherichia coli K12.
BACKGROUND
Escherichia coli K12 is a laboratory strain considered nonpathogenic. The purpose of this study was to examine the effect of E. coli K12 infection on colonic structure and function.


METHODS
Suckling rabbits were infected at 10 days of age with 6 x 10(9) CFU E. coli by intragastric inoculation and were examined 4 to 5 days later. Segments of ileum and proximal and distal colon were removed for light and electron microscopy, and NaCl transport was examined in vitro under short-circuited conditions in Ussing chambers.


RESULTS
Infection did not cause weight loss or diarrhea. Colonic mucosa was inflamed with infiltration by polymorphonuclear neutrophils mainly in the lamina propria. The proximal and distal colon exhibited reduced Na+ absorption. The proximal colon also showed increased Cl- secretion; the ileum was unaffected.


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 the potential to cause intestinal disease.
O'Loughlin
E V
EV
Department of Gastroenterology, Royal Alexandra Hospital for Children, Westmead, New South Wales, Australia.
Zhe
L
L
Buret
A
A
Bell
C
C
Robins-Browne
R M
RM
Elliott
E J
EJ
D000818:Animals; D000833:Animals, Suckling; D002712:Chlorides / Q000378:metabolism; D003106:Colon / Q000378:metabolism* / Q000473:pathology* / Q000648:ultrastructure; D004195:Disease Models, Animal; D004848:Epithelium / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D004926:Escherichia coli / Q000145:classification; D004927:Escherichia coli Infections / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D007082:Ileum / Q000378:metabolism / Q000473:pathology; D007408:Intestinal Absorption / Q000502:physiology; D007413:Intestinal Mucosa / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D017136:Ion Transport; D008854:Microscopy, Electron; D011817:Rabbits; D012964:Sodium / Q000493:pharmacokinetics
D002712:Chlorides; D012964:Sodium