Inhibition of translocation of viable Escherichia coli from the gastrointestinal tract of mice by bacterial antagonism

Abstract

The incidence of translocation of viable E. coli C25 from the gastrointestinal [G-I] tract to the mesenteric lymph nodes was compared in gnotobiotic mice colonized with only E. coli C25 and in gnotobiotic mice colonized with E. coli C25 plus the whole cecal flora from specific pathogen-free mice. The population levels of E. coli C25 in the ilea and ceca of these mice were compared. E. coli C25 maintained high population levels in the G-I tracts of the monoassociated gnotobiotes and the incidence of translocation to the mesenteric lymph nodes was 100%. G-I population levels of E. coli C25 were reduced drastically in the gnotobiotes associated with E. coli C25 and a cecal flora with a concomitant reduction in the incidence of translocation of E. coli C25 from 100 to 0%. A decrease in the numbers of viable E. coli C25/mesenteric lymph node accompanied the decrease in E. coli C25 population levels in the G-I tracts of these mice. High population level of E. coli C25 in the G-I tracts of monoassociated gnotobiotic mice appear to promote translocation of viable E. coli C25 to the mesenteric lymph nodes. Bacterial antagonism of E. coli population levels in conventional mice could be 1 mechanism whereby viable E. coli are confined to the G-I tract.