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Date of Original Version



Biochemistry, Microbiology and Molecular Genetics


The ability of Escherichia coli to survive stress during growth in different environments is, in large part, dependent onrpoS and the genes that comprise the rpoSregulon. E. coli BJ4 and an isogenic BJ4 rpoSmutant were used to examine the influence of the rpoS gene on E. coli colonization of the streptomycin-treated mouse large intestine. Colonization experiments in which the wild-typeE. coli BJ4 and its rpoS mutant were fed individually as well as simultaneously to mice suggested that E. coli BJ4 does not face prolonged periods of nutrient starvation in the mouse large intestine and that the rpoS regulon is not expressed during long-term colonization after adaptation of the bacteria to the gut environment.