TABLE 1.

Bacterial strains used in this study

Strain	Serotype	Relevant characteristic	Sourceb
E. coli Nissle 1917 wild type	O6:K5:H1	Probiotic strain	ACS
E. coli Nissle mutant strain			IMBI
E. coli CFT073Δhlya	O6:K2:H1	Intestinal isolate	IMBI
E. coli JM109 ATCC 53323	Orough:H48	Reference strain	IMBI
E. coli PZ 720	O83:K24:H31	Probiotic strain	ACS
E. coli W536	O6:K15:H31	Uropathogenic strain	IMBI
E. coli DH5α		Reference strain	IMBI
E. coli PZ 830	O4:H−	Clinical isolate	ACS
E. coli ATCC 25922		Reference strain	DSMZ
S. enterica serovar Enteritidis		Intestinal isolate	RBS

^aDeletion of toxin alpha-hemolysin.

^bACS, Ardeypharm Collection of Strains (fecal isolates); DSMZ, Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany; IMBI, strain collection of the Institute of Molecular Biology of Infection, University of Würzburg, Würzburg, Germany; RBS, clinical isolate from the Robert Bosch Hospital, Stuttgart, Germany.