title: Quorum sensing has an unexpected role in virulence in the model pathogen Citrobacter rodentium.
abstract: The bacterial mouse pathogen Citrobacter rodentium causes attaching and effacing (AE) lesions in the same manner as pathogenic Escherichia coli, and is an important model for this mode of pathogenesis. Quorum sensing (QS) involves chemical signalling by bacteria to regulate gene expression in response to cell density. E. coli has never been reported to have N-acylhomoserine lactone (AHL) QS, but it does utilize luxS-dependent signalling. We found production of AHL QS signalling molecules by an AE pathogen, C. rodentium. AHL QS is directed by the croIR locus and a croI mutant is affected in its surface attachment, although not in Type III secretion. AHL QS has an important role in virulence in the mouse as, unexpectedly, the QS mutant is hypervirulent; by contrast, we detected no impact of luxS inactivation. Further study of QS in Citrobacter should provide new insights into AE pathogenesis. As the croIR locus might have been horizontally acquired, AHL QS might exist in some strains of pathogenic E. coli.
authors.affiliation: Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Coulthurst
authors.forename: Simon
authors.initials: S
authors.lastname: Clare
authors.forename: Terry J
authors.initials: TJ
authors.lastname: Evans
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Foulds
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Roberts
authors.forename: Martin
authors.initials: M
authors.lastname: Welch
authors.forename: Gordon
authors.initials: G
authors.lastname: Dougan
authors.forename: George P C
authors.initials: GP
authors.lastname: Salmond
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics; D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects; D002876:Chromosomes, Bacterial; D044082:Citrobacter rodentium / Q000472:pathogenicity*; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005260:Female; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D051379:Mice; D008809:Mice, Inbred C3H; D009154:Mutation; D020161:Physical Chromosome Mapping; D053038:Quorum Sensing; D012997:Solvents / Q000494:pharmacology; D013047:Specific Pathogen-Free Organisms; D014774:Virulence
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D012997:Solvents; C088386:homoserine lactone; D015107:4-Butyrolactone; D004121:Dimethyl Sulfoxide