Population of Salmonella typhimurium in the cecum of gnotobiotic chickens.

To test the interaction of various species of bacteria with Salmonella typhimurium, levels of S. typhimurium were measured in the cecum of gnotobiotic chickens inoculated with various test bacteria and subsequently with S. typhimurium. The population of S. typhimurium was suppressed in the cecum of chickens previously inoculated with Escherichia coli. Populations of Bacteroides vulgatus, Clostridium perfringens, Bifidobacterium thermophilum, or Lactobacillus acidophilus were transiently, though not significantly, suppressed by S. typhimurium. Inoculation of chickens with C. perfringens caused a terminal increase in the population of S. typhimurium. Thus the effect of cecal contents on reducing the levels of S. typhimurium in the cecum may be due to the presence of E. coli in the cecal contents.