Observations on the in vivo and in vitro competition between strains of Escherichia coli isolated from the human gut

Regular exmination of Escherichia coli in faecal samples provided information about the outcome of competition in vivo and enabled two successful competing organisms to be selected for in vitro studies. A continuous flow culture technique was used in an attempt to reproduce the interactions that occurred between these two strains in the human gut. Some success was achieved in showing that changes in the chemostat environment, similar to those thought to be of significance in the gut, were followed by the establishment of the in vivo patterns of dominance.