title: Shiga toxin-producing Escherichia coli O157 : H7 shows an increased pathogenicity in mice after the passage through the gastrointestinal tract of the same host.
abstract: Haemolytic uraemic syndrome (HUS) is a rare but life-threatening complication of Shiga toxin (Stx)-producing Escherichia coli (STEC) infections, characterized by acute renal failure, thrombocytopenia and haemolytic anaemia. Although the main infection route is the consumption of contaminated food or water, person-to-person transmission has been suggested in several situations. Moreover, epidemiological data indicate that the horizontal transmission of several pathogens, including STEC, among individuals of the same species requires significantly lower doses than those used in animal models infected with laboratory-cultured bacteria. Thus, the aim of this study was to evaluate whether the passage of a clinically isolated STEC strain through the gastrointestinal tract of mice affects its pathogenicity in mice. To test this, weaned mice were orally inoculated by gavage with either an E. coli O157:H7 isolate from an HUS patient, or the same strain recovered from stools after one or two successive passages through the gastrointestinal tract of the mice. We show that stool-recovered strains are able to induce a more generalized and persistent colonization than the parent strain. Furthermore, a 10(4)-fold-reduced inoculum of the stool-recovered strains still causes gut colonization and mouse mortality, which are not observed with the parent strain. These results indicate an increased pathogenicity in stool-recovered strains that may be associated with an increased ability to colonize the mouse intestine.
authors.affiliation: División Inmunología, Instituto de Medicina Experimental (CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina.
authors.forename: Romina J
authors.initials: RJ
authors.lastname: Fernandez-Brando
authors.affiliation: Servicio Fisiopatogenia, Instituto Nacional de Enfermedades Infecciosas - ANLIS 'Dr Carlos G. Malbrán', Buenos Aires, Argentina.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Miliwebsky
authors.affiliation: División Inmunología, Instituto de Medicina Experimental (CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina.
authors.forename: María Pilar
authors.initials: MP
authors.lastname: Mejías
authors.affiliation: Servicio Fisiopatogenia, Instituto Nacional de Enfermedades Infecciosas - ANLIS 'Dr Carlos G. Malbrán', Buenos Aires, Argentina.
authors.forename: Ariela
authors.initials: A
authors.lastname: Baschkier
authors.affiliation: División Inmunología, Instituto de Medicina Experimental (CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina.
authors.forename: Cecilia A
authors.initials: CA
authors.lastname: Panek
authors.affiliation: División Inmunología, Instituto de Medicina Experimental (CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina.
authors.forename: María Jimena
authors.initials: MJ
authors.lastname: Abrey-Recalde
authors.affiliation: División Inmunología, Instituto de Medicina Experimental (CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Cabrera
authors.affiliation: División Inmunología, Instituto de Medicina Experimental (CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina.
authors.forename: María Victoria
authors.initials: MV
authors.lastname: Ramos
authors.affiliation: Servicio Fisiopatogenia, Instituto Nacional de Enfermedades Infecciosas - ANLIS 'Dr Carlos G. Malbrán', Buenos Aires, Argentina.
authors.forename: Marta
authors.initials: M
authors.lastname: Rivas
authors.affiliation: División Inmunología, Instituto de Medicina Experimental (CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina.
authors.forename: Marina S
authors.initials: MS
authors.lastname: Palermo
mesh_terms: D000818:Animals; D019453:Escherichia coli O157 / Q000472:pathogenicity*; D005243:Feces / Q000382:microbiology; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012692:Serial Passage; D016019:Survival Analysis; D014774:Virulence