TABLE 1.

Strains used in this study

Strain	Description	Reference or source
JM109	K-12 laboratory strain	13
EIEC 6.81	Enteroinvasive strain E. coli 6.81	7
ED32	ED32 wild-type strain: stx negative, LEE negative, and SE-PAI positive	6
ED32 Δtia	ED32 strain (6) in which the gene tia has been inactivated by the partial replacement of the gene with a Km resistance cassette	This study
ED32 Δtia/pGEM_tia	ED32 Δtia strain carrying the plasmid pGEM_tia to complement the tia mutation	This study
ED97	ED97 wild-type strain: stx positive, LEE negative, and SE-PAI positive	6