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E. coli Nissle 1917 Affects Salmonella adhesion to porcine intestinal epithelial cells.

Schierack P, Kleta S, Tedin K, Babila JT, Oswald S, Oelschlaeger TA, Hiemann R, Paetzold S, Wieler LH - PLoS ONE (2011)

Bottom Line: Another E. coli strain expressing F1C fimbriae was also adherent to IPEC-J2 cells, and was similarly inhibitory against Salmonella invasion like EcN.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.

View Article: PubMed Central - PubMed

Affiliation: Institut für Mikrobiologie und Tierseuchen, Freie Universität Berlin, Berlin, Germany. Peter.Schierack@HS-Lausitz.de

ABSTRACT

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.

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Salmonella invasion gene regulation by E. coli supernatants.E. coli were cultivated in cell culture medium (DMEM HAM'S/F-12) until an OD600nm = 1. Supernatants were collected by centrifugation with subsequent sterile filtration. Subsequently, SL1344 fusion strains (SL1344 hilC-lacZ, SL1344 hilD-lacZ, SL1344 hilA-lacZ, SL1344 icgA(siiE)-lacZ) were cultivated in supernatants of EcN, E. coli 140815 or E. coli MG1655. B-Galactosidase activity was measured as previously described [25], [26]. The results shown are representative of at least two independent experiments. White bar: Salmonella grown in EcN supernatant, gray bar: Salmonella grown in E. coli 140815 supernatant, black bar: Salmonella grown in E. coli MG1655 supernatant, patterned bar: Salmonella grown in pure cell culture medium.
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pone-0014712-g009: Salmonella invasion gene regulation by E. coli supernatants.E. coli were cultivated in cell culture medium (DMEM HAM'S/F-12) until an OD600nm = 1. Supernatants were collected by centrifugation with subsequent sterile filtration. Subsequently, SL1344 fusion strains (SL1344 hilC-lacZ, SL1344 hilD-lacZ, SL1344 hilA-lacZ, SL1344 icgA(siiE)-lacZ) were cultivated in supernatants of EcN, E. coli 140815 or E. coli MG1655. B-Galactosidase activity was measured as previously described [25], [26]. The results shown are representative of at least two independent experiments. White bar: Salmonella grown in EcN supernatant, gray bar: Salmonella grown in E. coli 140815 supernatant, black bar: Salmonella grown in E. coli MG1655 supernatant, patterned bar: Salmonella grown in pure cell culture medium.

Mentions: As the previous results indicated that Salmonella adhesion - but not extracellular or intracellular Salmonella growth - was affected by EcN, we tested the effects of EcN supernatants on the expression of Salmonella invasion gene regulatory and dependent genes. Salmonella strains harboring lacZ fusions to the invasion locus regulatory genes hilC, hilD, hilA, and the SPI4-encoded siiE gene were incubated with supernatants of EcN, E. coli 140815 or E. coli MG1655. As shown in Figure 9, expression of HilC was not affected by any of the three E. coli supernatants. HilD expression was slightly enhanced by all three E. coli supernatants and HilA and SiiE expressions were inhibited by all three E. coli supernatants.


E. coli Nissle 1917 Affects Salmonella adhesion to porcine intestinal epithelial cells.

Schierack P, Kleta S, Tedin K, Babila JT, Oswald S, Oelschlaeger TA, Hiemann R, Paetzold S, Wieler LH - PLoS ONE (2011)

Salmonella invasion gene regulation by E. coli supernatants.E. coli were cultivated in cell culture medium (DMEM HAM'S/F-12) until an OD600nm = 1. Supernatants were collected by centrifugation with subsequent sterile filtration. Subsequently, SL1344 fusion strains (SL1344 hilC-lacZ, SL1344 hilD-lacZ, SL1344 hilA-lacZ, SL1344 icgA(siiE)-lacZ) were cultivated in supernatants of EcN, E. coli 140815 or E. coli MG1655. B-Galactosidase activity was measured as previously described [25], [26]. The results shown are representative of at least two independent experiments. White bar: Salmonella grown in EcN supernatant, gray bar: Salmonella grown in E. coli 140815 supernatant, black bar: Salmonella grown in E. coli MG1655 supernatant, patterned bar: Salmonella grown in pure cell culture medium.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3040738&req=5

pone-0014712-g009: Salmonella invasion gene regulation by E. coli supernatants.E. coli were cultivated in cell culture medium (DMEM HAM'S/F-12) until an OD600nm = 1. Supernatants were collected by centrifugation with subsequent sterile filtration. Subsequently, SL1344 fusion strains (SL1344 hilC-lacZ, SL1344 hilD-lacZ, SL1344 hilA-lacZ, SL1344 icgA(siiE)-lacZ) were cultivated in supernatants of EcN, E. coli 140815 or E. coli MG1655. B-Galactosidase activity was measured as previously described [25], [26]. The results shown are representative of at least two independent experiments. White bar: Salmonella grown in EcN supernatant, gray bar: Salmonella grown in E. coli 140815 supernatant, black bar: Salmonella grown in E. coli MG1655 supernatant, patterned bar: Salmonella grown in pure cell culture medium.
Mentions: As the previous results indicated that Salmonella adhesion - but not extracellular or intracellular Salmonella growth - was affected by EcN, we tested the effects of EcN supernatants on the expression of Salmonella invasion gene regulatory and dependent genes. Salmonella strains harboring lacZ fusions to the invasion locus regulatory genes hilC, hilD, hilA, and the SPI4-encoded siiE gene were incubated with supernatants of EcN, E. coli 140815 or E. coli MG1655. As shown in Figure 9, expression of HilC was not affected by any of the three E. coli supernatants. HilD expression was slightly enhanced by all three E. coli supernatants and HilA and SiiE expressions were inhibited by all three E. coli supernatants.

Bottom Line: Another E. coli strain expressing F1C fimbriae was also adherent to IPEC-J2 cells, and was similarly inhibitory against Salmonella invasion like EcN.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.

View Article: PubMed Central - PubMed

Affiliation: Institut für Mikrobiologie und Tierseuchen, Freie Universität Berlin, Berlin, Germany. Peter.Schierack@HS-Lausitz.de

ABSTRACT

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.

Show MeSH
Related in: MedlinePlus