VARIATIONS IN THE CSGD PROMOTER OF ESCHERICHIA COLI O157:H7 ASSOCIATED WITHINCREASED VIRULENCE IN MICE AND INCREASED INVASION OF HEP-2 CELLS

Authors: Uhlich, Gaylen; Keen, James; Elder, Robert

Submitted to: Infection and Immunity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2001
Publication Date: 1/1/2002
Citation: Infection and Immunity. 2002. v. 70. p. 395-399.

Interpretive Summary: Single base-pair alterations in the promoter region of the csgD gene of Escherichia coli O157:H7 strains ATCC 43894 and ATCC 43895 are associated with two different bacterial populations with distinct phenotypes: a curli fiber-expressing, Congo red dye-binding phenotype and a form that neither expresses curli fibers nor binds Congo red dye. Red variants of each strain were more invasive for cultured HEp-2 cells than their respective white variants. An ATCC 43895 red variant, when given orally to female CD-1 mice, resulted in death of the mice quicker than a corresponding white variant. However, there were no differences in Shiga-toxin production between red and white variants indicating that the virulence and invasive differences were not due to variations in Shiga-toxin.

Technical Abstract: Promoter alterations in the csgD gene of Escherichia coli O157:H7 strains ATCC 43894 and ATCC 43895 are associated with variations in curli expression and the ability to bind Congo red dye. Red variants of each strain were more invasive for cultured HEp-2 cells than white variants. An ATCC 43895 red variant was more virulent than a white variant in a mouse model. However, there were no differences in Shiga-toxin production between red and white variants.