Motility allows S. Typhimurium to benefit from the mucosal defence

Stecher, Bärbel; Barthel, Manja; Schlumberger, Markus C.; Haberli, Lea; Rabsch, Wolfgang; Kremer, Marcus; Hardt, Wolf‐Dietrich

doi:10.1111/j.1462-5822.2008.01118.x

Cited by 181 publications

(179 citation statements)

References 46 publications

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“…This allows the pathogen to benefit from flagellar gene expression in favorable host environments. Flagellin is a proinflammatory molecule, and motile Salmonella grow more quickly than nonmotile strains in the inflamed intestine, because they are able to migrate to the nutrient-rich zone close to the epithelium (27). However, our data demonstrate that tight repression of flagellin is required for Salmonella to thrive in systemic tissues.…”

Section: Discussioncontrasting

confidence: 50%

Regulation of phenotypic heterogeneity permits Salmonella evasion of the host caspase-1 inflammatory response

Stewart¹,

Cummings

Johnson

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Sensing and adapting to the environment is one strategy by which bacteria attempt to maximize fitness in an unpredictable world; another is the stochastic generation of phenotypically distinct subgroups within a genetically clonal population. In culture, Salmonella Typhimurium populations are bistable for the expression of flagellin. We report that YdiV controls this expression pattern by preventing transcription of the sigma factor that recruits RNA polymerase to the flagellin promoter. Bistability ensues when the sigma factor is repressed in a subpopulation of cells, resulting in two phenotypes: flagellin expressors and flagellin nonexpressors. Although the ability to swim is presumably a critical survival trait, flagellin activates eukaryotic defense pathways, and Salmonella restrict the production of flagellin during systemic infection. Salmonella mutants lacking YdiV are unable to fully repress flagellin at systemic sites, rendering them vulnerable to caspase-1 mediated colonization restriction. Thus, a regulatory mechanism producing bistability also impacts Salmonella virulence.

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Section: Discussioncontrasting

confidence: 50%

Regulation of phenotypic heterogeneity permits Salmonella evasion of the host caspase-1 inflammatory response

Stewart¹,

Cummings

Johnson

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…The eutT gene encodes an adenosyltransferase, which is used to activate EutR, and in turn triggers transcription of the operon (68). Two of the genes, eutM and eutN, partially encode a metabolosome with the products of eutSLK, which encode the shell proteins of the metabolosome (74). The role of this structure was proposed to be to concentrate low levels of ethanolamine catabolic enzymes (10).…”

Section: Discussionmentioning

confidence: 99%

Salmonella enterica Serovar Typhimurium Colonizing the Lumen of the Chicken Intestine Grows Slowly and Upregulates a Unique Set of Virulence and Metabolism Genes

Harvey¹,

Watson²,

Hulme

et al. 2011

Infect Immun

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The pattern of global gene expression in Salmonella enterica serovar Typhimurium bacteria harvested from the chicken intestinal lumen (cecum) was compared with that of a late-log-phase LB broth culture using a whole-genome microarray. Levels of transcription, translation, and cell division in vivo were lower than those in vitro. S. Typhimurium appeared to be using carbon sources, such as propionate, 1,2-propanediol, and ethanolamine, in addition to melibiose and ascorbate, the latter possibly transformed to D-xylulose. Amino acid starvation appeared to be a factor during colonization. Bacteria in the lumen were non-or weakly motile and nonchemotactic but showed upregulation of a number of fimbrial and Salmonella pathogenicity island 3 (SPI-3) and 5 genes, suggesting a close physical association with the host during colonization. S. Typhimurium bacteria harvested from the cecal mucosa showed an expression profile similar to that of bacteria from the intestinal lumen, except that levels of transcription, translation, and cell division were higher and glucose may also have been used as a carbon source.

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“…Immunofluorescence. For detecting S. Tm and Ec 8178 in the gut lumen in situ, cecal tissues were recovered and treated as described (45). Briefly, the tissue was fixed in paraformaldehyde (4% in PBS, pH 7.4 overnight, 4°C), washed with PBS, equilibrated in PBS (20% sucrose, 0.1% NaN 3 overnight, 4°C), embedded in O.C.T.…”

Section: Methodsmentioning

confidence: 99%

Gut inflammation can boost horizontal gene transfer between pathogenic and commensal Enterobacteriaceae

Stecher

Denzler

Maier

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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423

399

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The mammalian gut harbors a dense microbial community interacting in multiple ways, including horizontal gene transfer (HGT). Pangenome analyses established particularly high levels of genetic flux between Gram-negative Enterobacteriaceae. However, the mechanisms fostering intraenterobacterial HGT are incompletely understood. Using a mouse colitis model, we found that Salmonella-inflicted enteropathy elicits parallel blooms of the pathogen and of resident commensal Escherichia coli. These blooms boosted conjugative HGT of the colicin-plasmid p2 from Salmonella enterica serovar Typhimurium to E. coli. Transconjugation efficiencies of ∼100% in vivo were attributable to high intrinsic p2-transfer rates. Plasmid-encoded fitness benefits contributed little. Under normal conditions, HGT was blocked by the commensal microbiota inhibiting contact-dependent conjugation between Enterobacteriaceae. Our data show that pathogen-driven inflammatory responses in the gut can generate transient enterobacterial blooms in which conjugative transfer occurs at unprecedented rates. These blooms may favor reassortment of plasmid-encoded genes between pathogens and commensals fostering the spread of fitness-, virulence-, and antibiotic-resistance determinants.bacterial evolution | hospital-acquired infection | mucosal immune response | plasmid spread

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Motility allows S. Typhimurium to benefit from the mucosal defence

Cited by 181 publications

References 46 publications

Regulation of phenotypic heterogeneity permits Salmonella evasion of the host caspase-1 inflammatory response

Regulation of phenotypic heterogeneity permits Salmonella evasion of the host caspase-1 inflammatory response

Salmonella enterica Serovar Typhimurium Colonizing the Lumen of the Chicken Intestine Grows Slowly and Upregulates a Unique Set of Virulence and Metabolism Genes

Gut inflammation can boost horizontal gene transfer between pathogenic and commensal Enterobacteriaceae

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