title: Comparison between virulence characteristics of dominant and non-dominant Escherichia coli strains of the gut and their interaction with Caco-2 cells.
abstract: Escherichia coli strains are normal inhabitants of the gut and are normally found in the faeces of the host at different population sizes. We characterised faecal E. coli of 45 healthy male (n = 17) and female (n = 28) volunteers by testing 28 isolates from each individual. These isolates were typed and divided into dominant (if constituted >50% of the population tested) and non-dominant types in each individual. Representative strains of each dominant and non-dominant type were tested for their virulence gene profiles, their ability to form biofilm, adhere to, invade and translocate through a gut epithelial cell line (Caco-2 cells). Strains belonging to dominant types adhered significantly more to Caco-2 cells than non-dominant strains (5.7 ± 0.3 versus 4.3.± 0.13 CFU/cell mean ± SEM, P = 0.0003). They also invaded (135 ± 6 versus 63 ± 13 CFU) and translocated through Caco-2 cells (84 ± 5 versus 32 ± 9 CFU) significantly more than non-dominant strains (P < 0.0001 and P = 0.0002, respectively). Moreover, dominant strains showed the ability to form significantly more biofilm than non-dominant strains (1.1 ± 0.01 versus 0.5 ± 0.1 OD600, P < 0.0001). Majority (51%) of the strains belonged to phylogroup D followed by B2 (23%). Furthermore, out of 25 virulence genes tested, kpsMTII, papC and papG allele III were found to be significantly higher among dominant than non-dominant strains. Our results suggest that E. coli strains dominating the gut may have virulence properties that enable them to efficiently interact with the gut epithelium and translocate under predisposing conditions of the host.
authors.affiliation: School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Owrangi
authors.affiliation: School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia.
authors.forename: N
authors.initials: N
authors.lastname: Masters
authors.affiliation: School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia.
authors.forename: T L
authors.initials: TL
authors.lastname: Vollmerhausen
authors.affiliation: School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia.
authors.forename: C
authors.initials: C
authors.lastname: O'Dea
authors.affiliation: School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Kuballa
authors.affiliation: School of Health and Sport Sciences, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia. Electronic address: mkatouli@usc.edu.au.
authors.forename: M
authors.initials: M
authors.lastname: Katouli
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D018830:Adhesins, Escherichia coli / Q000235:genetics; D001422:Bacterial Adhesion; D018988:Bacterial Translocation; D018441:Biofilms; D018938:Caco-2 Cells; D004847:Epithelial Cells / Q000382:microbiology; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D005243:Feces / Q000382:microbiology; D005260:Female; D036781:Fimbriae Proteins / Q000235:genetics; D041981:Gastrointestinal Tract / Q000382:microbiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D007410:Intestinal Diseases / Q000382:microbiology*; D008297:Male; D018272:Porins / Q000235:genetics; D015995:Prevalence; D012737:Sex Factors; D014774:Virulence / Q000235:genetics
chemical_list: D018528:ATP-Binding Cassette Transporters; D018830:Adhesins, Escherichia coli; D029968:Escherichia coli Proteins; C092426:PapG protein, E coli; D018272:Porins; C111243:atpG protein, E coli; C068103:kpsT protein, E coli; D036781:Fimbriae Proteins
keywords: Caco-2 cells; E. coli; Invasion; Translocation; Virulence genes