title: Systematic Analysis of Two-Component Systems in Citrobacter rodentium Reveals Positive and Negative Roles in Virulence.
abstract: Citrobacter rodentium is a murine pathogen used to model intestinal infections caused by the human diarrheal pathogens enterohemorrhagic and enteropathogenic Escherichia coli During infection, bacteria use two-component systems (TCSs) to detect changing environmental cues within the host, allowing for rapid adaptation by altering the expression of specific genes. In this study, 26 TCSs were identified in C. rodentium, and quantitative PCR (qPCR) analysis showed that they are all expressed during murine infection. These TCSs were individually deleted, and the in vitro and in vivo effects were analyzed to determine the functional consequences. In vitro analyses only revealed minor differences, and surprisingly, type III secretion (T3S) was only affected in the ΔarcA strain. Murine infections identified 7 mutants with either attenuated or increased virulence. In agreement with the in vitro T3S assay, the ΔarcA strain was attenuated and defective in colonization and cell adherence. The ΔrcsB strain was among the most highly attenuated strains. The decrease in virulence of this strain may be associated with changes to the cell surface, as Congo red binding was altered, and qPCR revealed that expression of the wcaA gene, which has been implicated in colanic acid production in other bacteria, was drastically downregulated. The ΔuvrY strain exhibited increased virulence compared to the wild type, which was associated with a significant increase in bacterial burden within the mesenteric lymph nodes. The systematic analysis of virulence-associated TCSs and investigation of their functions during infection may open new avenues for drug development.
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.
authors.forename: Jenny-Lee
authors.initials: JL
authors.lastname: Thomassin
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.
authors.forename: Jean-Mathieu
authors.initials: JM
authors.lastname: Leclerc
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.
authors.forename: Natalia
authors.initials: N
authors.lastname: Giannakopoulou
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.
authors.forename: Kristiana
authors.initials: K
authors.lastname: Salmon
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Portt
authors.affiliation: Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, QC, Canada.
authors.forename: France
authors.initials: F
authors.lastname: Daigle
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada Herve.le-moual@mcgill.ca Samantha.gruenheid@mcgill.ca.|Microbiome and Disease Tolerance Centre, McGill University, Montreal, QC, Canada.|Faculty of Dentistry, McGill University, Montreal, QC, Canada.
authors.forename: Hervé
authors.initials: H
authors.lastname: Le Moual
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada Herve.le-moual@mcgill.ca Samantha.gruenheid@mcgill.ca.|Microbiome and Disease Tolerance Centre, McGill University, Montreal, QC, Canada.
authors.forename: Samantha
authors.initials: S
authors.lastname: Gruenheid
mesh_terms: D000818:Animals; D058491:Bacterial Load; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D044082:Citrobacter rodentium / Q000472:pathogenicity / Q000502:physiology*; D004195:Disease Models, Animal; D004756:Enterobacteriaceae Infections / Q000382:microbiology* / Q000401:mortality; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D054884:Host-Pathogen Interactions; D006801:Humans; D051379:Mice; D010641:Phenotype; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins
keywords: Citrobacter; attaching/effacing pathogens; bacterial pathogenesis; gastrointestinal infection; host-pathogen interactions; mouse models; two-component regulatory systems