SHIGA TOXIN-PRODUCING Escherichia coli O157:H7 SHOW AN INCREASED PATHOGENICITY IN MICE AFTER THE PASSAGE THROUGH THE GASTROINTESTINAL TRACT OF THE SAME HOST

FERNANDEZ BRANDO, ROMINA J; MILIWEBSY, ELIZABETH; MEJIAS, PILAR; BASCHIERK, ARIELA; PANEK, ANALIA CECILIA; ABREY-RECALDE, MARIA JIMENA; CABRERA, G; RAMOS, MARIA VICTORIA; RIVAS, M; PALERMO, MARINA SANDRA

JOURNAL OF MEDICAL MICROBIOLOGY

SOC GENERAL MICROBIOLOGY

Lugar: Edimburgo; Año: 2012 vol. 61 p. 852 - 859

0022-2615

Hemolytic Uremic 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 hemolytic anemia. 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 clinical-isolated STEC strain through the gastrointestinal tract of mice affects the pathogenicity in mice. To test this, weaned mice were orally inoculated by gavage with either an E. coli O157:H7 isolated from an HUS patient, or the same strain recovered from stools after one or two successive passages through the gastrointestinal tract of mice. We show that stool-recovered strains are able to induce a more generalized and persistent colonization than the parent strain. Furthermore, a 104-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.