EPITHELIAL, MUCUS AND LUMEN SUBPOPULATIONS OF ESCHERICHIA-COLI IN THELARGE-INTESTINE OF CONVENTIONAL AND GNOTOBIOTIC-RATS

Germ-free and conventional rats were dosed per as with two Echerichia coli strains and killed 2 or 5 days after dosing. Two separation metho ds to separate the intestinal E. coli population into lumen-, mucus- a nd epithelium-associated subpopulations were compared using traditiona l quantitative bacteriology and a histochemical method based on staini ng of cryostat sections with Alcian Blue. The majority of the E. coli cells were situated in the lumen contents. This was the case for the t est organisms as well as for the indigenous E. coli. The two separatio n methods performed similarly. The two E. call test strains showed a c lear difference in colonisation ability. However, the relative distrib ution of the three different subpopulations was the same regardless of the colonisation ability of the test strain.