Routes of E. coli 055 bacterial penetration through the intestinal wall in gnotobiotic and ordinary animals]

Peculiarities of permeability of intestinal barrier in germfree animals for enteropathogenic E. coli 055 were studied. Both germfree and conventional guinea pigs and rats were used. An increase of bacteriemia was revealed in gnotobiotes during the first day of oral E. coli 055 monocontamination; bacteriemia was transient in conventional animals. Under electron microscopy alterations of intercellular contacts and formation of spaces between enterocytes containing numerous microorganisms were found in the intestinal mucous membrane in gnotobiotes. Also more pronounced changes of microvessels of the intestinal mucous membrane were discovered in gnotobiotes. The processes of ingestionan and digestion of Escherichia coli by enterocytes and leukocytes were noted in conventional animals. The revealed derangements of the intestinal barrier in gnotobiotes explain the cause of higher bacteriemia in germfree animals. An important role of the microbial factor in the formation of intestinal barrier is indicated by the data obtained.