title: The probiotic Escherichia coli strain Nissle 1917 interferes with invasion of human intestinal epithelial cells by different enteroinvasive bacterial pathogens.
abstract: The probiotic Escherichia coli strain Nissle 1917 (Mutaflor) of serotype O6:K5:H1 was reported to protect gnotobiotic piglets from infection with Salmonella enterica serovar Typhimurium. An important virulence property of Salmonella is invasion of host epithelial cells. Therefore, we tested for interference of E. coli strain Nissle 1917 with Salmonella invasion of INT407 cells. Simultaneous administration of E. coli strain Nissle 1917 and Salmonella resulted in up to 70% reduction of Salmonella invasion efficiency. Furthermore, invasion of Yersinia enterocolitica, Shigella flexneri, Legionella pneumophila and even of Listeria monocytogenes were inhibited by the probiotic E. coli strain Nissle 1917 without affecting the viability of the invasive bacteria. The observed inhibition of invasion was not due to the production of microcins by the Nissle 1917 strain because its isogenic microcin-negative mutant SK22D was as effective as the parent strain. Reduced invasion rates were also achieved if strain Nissle 1917 was separated from the invasive bacteria as well as from the INT407 monolayer by a membrane non-permeable for bacteria. We conclude E. coli Nissle 1917 to interfere with bacterial invasion of INT407 cells via a secreted component and not relying on direct physical contact with either the invasive bacteria or the epithelial cells.
authors.affiliation: Institut für Molekulare Infektionsbiologie, Röntgenring 11, Universität Würzburg, 97070 Würzburg, Germany.
authors.forename: Artur
authors.initials: A
authors.lastname: Altenhoefer
authors.forename: Sibylle
authors.initials: S
authors.lastname: Oswald
authors.forename: Ulrich
authors.initials: U
authors.lastname: Sonnenborn
authors.forename: Corinne
authors.initials: C
authors.lastname: Enders
authors.forename: Juergen
authors.initials: J
authors.lastname: Schulze
authors.forename: Joerg
authors.initials: J
authors.lastname: Hacker
authors.forename: Tobias A
authors.initials: TA
authors.lastname: Oelschlaeger
mesh_terms: D000898:Antibiosis; D001419:Bacteria / Q000472:pathogenicity*; D001430:Bacteriocins / Q000096:biosynthesis / Q000235:genetics; D002460:Cell Line; D004847:Epithelial Cells / Q000382:microbiology*; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology*; D016952:Legionella pneumophila / Q000254:growth & development / Q000472:pathogenicity; D008089:Listeria monocytogenes / Q000254:growth & development / Q000472:pathogenicity; D019936:Probiotics; D012486:Salmonella typhimurium / Q000254:growth & development / Q000472:pathogenicity; D012763:Shigella flexneri / Q000254:growth & development / Q000472:pathogenicity; D015008:Yersinia enterocolitica / Q000254:growth & development / Q000472:pathogenicity
chemical_list: D001430:Bacteriocins; C020411:microcin