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P2-38 Investigation of Adherence Strategies of Environmental Escherichia coli to Food Samples and Human Epithelial Cells

Tuesday, July 30, 2013
Exhibit Hall (Charlotte Convention Center)
Krystal Shortlidge, University of Delaware, Newark, DE
Sarah Markland, University of Delaware, Wilmington, DE
Kyle LeStrange, University of Delaware, Newark, DE
Manan Sharma, U.S. Department of Agriculture-ARS, Beltsville, MD
Kalmia Kniel, University of Delaware, Newark, DE
Introduction: Avian pathogenic Escherichia coli (APEC) are zoonotic members of the extraintestinal pathogenic E. coli pathotype (ExPEC). Although APEC are not normally associated with disease in humans like enterohemorraghic E. coli(EHEC), APEC isolates have been identified on foods and as carrying EHEC genes.  Outbreak entero-aggregative (EAEC) strains have also been characterized as Shiga toxin positive. In this study, persistence on leafy greens, attachment to chicken breast and interaction with intestinal cells were assessed.

Purpose: The objective of this study was to evaluate the ability of 30 strains of environmental and clinical UPEC outbreak EAEC, and EHEC isolates to attach to chicken tissue and human intestinal cells. 

Methods: Multiplex PCR was used to assess the presence of 12 EHEC and UPEC genes in E. coli strains (n = 30).  Cells were inoculated on basil plants, retail chicken breast samples or human cells grown to confluency in 6-well plates. E. coliattachment to HCT-8 cells (human ileocecal) was compared to that of CaCo-2 cells (human colonic). Multivariate correlations were generated using JMP Software.

Results: Statistical analysis showed several strong correlations between the number of EHEC or UPEC virulence genes and attachment to various matrices. Moderate correlations (r = 0.51) indicated that attachment to chicken was higher for APEC and UPEC strains compared to EHEC strains. The UPEC isolate attached most strongly to chicken and APEC isolates persisted for longer periods on leafy greens indicating enhanced attachment. Attachment to human HCT-8 cells tended to be higher for strains containing low numbers of EHEC virulence genes (r = 0.98) but was weakly correlated with UPEC strains (r = 0.31). Strains with more EHEC genes strongly correlated with higher survival on basil, lettuce, and spinach (r = 0.98). 

Significance: The number and type of EHEC and/or UPEC virulence genes present within the genome of E. coli may correlate to their ability to persist on food and human cell surfaces.

Back to: Poster Session 2 - Pathogens, Antimicrobials
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