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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Molecular Characterization of Foodborne Pathogens Research » Research » Publications at this Location » Publication #313808

Title: Virulence gene profiles of shiga toxin-producing Escherichia coli isolated from fecal samples of finishing swine

Author
item BARANZONI, GIANMARCO - University Of Bologna, Italy
item Fratamico, Pina
item Bagi, Lori
item DELANNOY, SABINE - French Agency For Food, Environmental And Occupational Health & Safety (ANSES)
item FACH, PATRICK - French Agency For Food, Environmental And Occupational Health & Safety (ANSES)
item TSENG, MARION - Michigan State University
item FUNK, JULIE - Michigan State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/23/2015
Publication Date: 5/30/2015
Citation: Baranzoni, G., Fratamico, P.M., Bagi, L.K., Delannoy, S., Fach, P., Tseng, M., Funk, J. 2015. Virulence gene profiles of shiga toxin-producing Escherichia coli isolated from fecal samples of finishing swine. Meeting Abstract. meeting abstract.

Interpretive Summary:

Technical Abstract: Shiga toxin-producing Escherichia coli (STEC) are important pathogens responsible for food-borne outbreaks and serious illness including hemorrhagic colitis and hemolytic uremic syndrome. Certain STEC serogroups may cause edema disease in swine; and similar to cattle, swine have been shown to be a reservoir for STEC. Pork products have been linked with outbreaks associated with E. coli O157:H7 and STEC O111. STEC strains (n=186), isolated from fecal samples of late-finisher pigs were serotyped and tested by PCR to confirm for the presence of the stx1, stx2 or stx2e genes. The strains were then tested for the presence of 69 virulence genes, 14 O-group-associated genes and 11 H-group-associated genes by a high-throughput real-time PCR array system. The STEC strains belonged to 26 O-serogroups, including O2, O5, O7, O8, O9, O15, O20, O91, O96, O101, O103, O121, O159 and O163, which were previously associated with human cases, and other serogroups. Eighty one percent of the isolated strains carried stx2e, 15.1% were positive for stx1, and the remaining 3.8% encoded a stx2 variant that was not subtype stx2e. Serogroups O15, O152, O163 and OX18 carried stx1 while serogroups O159 and O7 carried stx2 (non-stx2e). Serogroups O-non-typeable, O20, and O91 only carried either stx1 or stx2e, and the virulence gene profiles of these strains varied. The 186 strains examined carried a variety of virulence genes, including genes encoding toxins, hemolysins, and proteins involved in the adhesion to host cells. Only one isolate carried eae beta, nleF, and nleH1-2, and it was also positive for stx2e, espM2, lpfA-O26, lpfA-O113, astA, orfA, orfB, ehaA and paa. Other virulence gene profiles, including: stx2e iha, paa, terE, and ureD; ecs1763, STa, and lpfA0113; or both combined were found in 5.9%, 7.5%, and 3.2% of the isolates, respectively. These data indicate that swine STEC represent a heterogeneous group of organisms, and the characterization of the virulence gene profiles provides new insights on the potential of swine STEC as zoonotic pathogens.