title: Increased EHEC survival and virulence gene expression indicate an enhanced pathogenicity upon simulated pediatric gastrointestinal conditions.
abstract: Enterohemorrhagic Escherichia coli (EHEC) are major foodborne pathogens that constitute a serious public health threat, mainly in young children. Shiga toxins (Stx) are the main virulence determinants of EHEC pathogenesis but adhesins like intimin (eae) and Long polar fimbriae (Lpf) also contribute to infection. The TNO GastroIntestinal Model (TIM) was used for a comparative study of EHEC O157:H7 survival and virulence under adult and child digestive conditions.
  
  
  
  Survival kinetics in the in vitro digestive tract were determined by plating while bacterial viability was assessed by flow cytometry analysis. Expression of stx, eae, and lpf genes was followed by reverse transcriptase-quantitative PCR (RT-qPCR) and Stx production was measured by ELISA (enzyme-linked immunosorbent assay).
  
  
  
  Upon gastrointestinal passage, a higher amount of viable cells was found in the simulated ileal effluents of children compared to that of adults (with 34 and 6% of viable cells, respectively). Expression levels of virulence genes were up to 125-fold higher in children. Stx was detected only in child ileal effluents.
  
  
  
  Differences in digestive physicochemical parameters may partially explain why children are more susceptible to EHEC infection than adults. Such data are essential for a full understanding of EHEC pathogenesis and would help in designing novel therapeutic approaches.
authors.affiliation: EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.|CMet, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium.
authors.forename: Charlène
authors.initials: C
authors.lastname: Roussel
authors.affiliation: EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.|M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Cordonnier
authors.affiliation: EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.|UMR 5557 Ecologie Microbienne, Research Group on Bacterial Opportunistic Pathogens and Environment, CNRS, VetAgro Sup and Université de Lyon, Lyon, France.|Unité CALYTISS, VetAgro Sup, Lempdes, France.
authors.forename: Wessam
authors.initials: W
authors.lastname: Galia
authors.affiliation: EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Le Goff
authors.affiliation: EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.|M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Thévenot
authors.affiliation: EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Chalancon
authors.affiliation: EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: Monique
authors.initials: M
authors.lastname: Alric
authors.affiliation: UMR 5557 Ecologie Microbienne, Research Group on Bacterial Opportunistic Pathogens and Environment, CNRS, VetAgro Sup and Université de Lyon, Lyon, France.|Laboratoire d'Etude des Microorganismes Alimentaires Pathogènes, French National Reference Laboratory for Escherichia coli including Shiga Toxin-Producing E. coli, VetAgro Sup, Université de Lyon, Marcy l'Etoile, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Thevenot-Sergentet
authors.affiliation: Unité CALYTISS, VetAgro Sup, Lempdes, France.
authors.forename: Francoise
authors.initials: F
authors.lastname: Leriche
authors.affiliation: CMet, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium.
authors.forename: Tom
authors.initials: T
authors.lastname: Van de Wiele
authors.affiliation: M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne, Université d'Auvergne, Clermont-Ferrand, France.|Service de Bactériologie, CHU de Clermont-Ferrand, Clermont-Ferrand, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Livrelli
authors.affiliation: EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Blanquet-Diot
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D002648:Child; D054324:Enterohemorrhagic Escherichia coli / Q000235:genetics* / Q000254:growth & development* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D005434:Flow Cytometry; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D007421:Intestine, Small / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D022621:Shiga Toxin / Q000235:genetics / Q000378:metabolism*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D018829:Adhesins, Bacterial; D037521:Virulence Factors; D022621:Shiga Toxin