Background: The probiotic Escherichia coli strain Nissle 1917 (EcN) has been
shown to interfere in a human in vitro model with the invasion of several
bacterial pathogens into epithelial cells, but the underlying molecular
mechanisms are not known. Methodology/Principal Findings: In this study, we
investigated the inhibitory effects of EcN on Salmonella Typhimurium invasion
of porcine intestinal epithelial cells, focusing on EcN effects on the various
stages of Salmonella infection including intracellular and extracellular
Salmonella growth rates, virulence gene regulation, and adhesion. We show that
EcN affects the initial Salmonella invasion steps by modulating Salmonella
virulence gene regulation and Salmonella SiiE-mediated adhesion, but not
extra- and intracellular Salmonella growth. However, the inhibitory activity
of EcN against Salmonella invasion always correlated with EcN adhesion
capacities. EcN mutants defective in the expression of F1C fimbriae and
flagellae were less adherent and less inhibitory toward Salmonella invasion.
Another E. coli strain expressing F1C fimbriae was also adherent to IPEC-J2
cells, and was similarly inhibitory against Salmonella invasion like EcN.
Conclusions: We propose that EcN affects Salmonella adhesion through secretory
components. This mechanism appears to be common to many E. coli strains, with
strong adherence being a prerequisite for an effective reduction of SiiE-
mediated Salmonella adhesion.
600 Technik, Medizin, angewandte Wissenschaften::630 Landwirtschaft::636 Viehwirtschaft
E. coli Nissle 1917 Affects Salmonella Adhesion to Porcine Intestinal
PLoS ONE 6 (2011), 2, e14712
Institut für Mikrobiologie und Tierseuchen