抄録
While the constancy of normal enteric flora and its resistance to superinfection has been observed rather frequently, little is known about the underlying mechanisms.
The present paper suggests that the mechanism by which E. coli inhibited the growth of S. flexneri in CF cultures and, by implication, also in the intestine might be based on competition of these bacteria for fermentable carbon sources under the prevailing highly reduced conditions. It will be shown that antagonism by a resident E. coli against newly introduced strains is abolished in the presence of a fermentable carbon source which can be metabolized by the new inoculum but not by the established flora. It was concluded that a resident strain resisted replacement because it was there first and was already adapted, which much of the invader strain was washed out during the period of adaptation. There was no evidence of inhibitory substances active against invader strains.
The present work adds further evidence to earlier observations that the environmental conditions in CF cultures reremble those in the intestinal tract of man and animals. The results are discussed with respect to the qualities which a normal enteric flora must possess in order to resist the invasion of enteric pathogens.
