A novel murine infection model for Shiga toxin–producing Escherichia coli
Emily M. Mallick, … , John M. Leong, David B. Schauer
Emily M. Mallick, … , John M. Leong, David B. Schauer
Published October 8, 2012
Citation Information: J Clin Invest. 2012;122(11):4012-4024. https://doi.org/10.1172/JCI62746.
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Technical Advance Infectious disease

A novel murine infection model for Shiga toxin–producing Escherichia coli

Abstract

Enterohemorrhagic E. coli (EHEC) is an important subset of Shiga toxin–producing (Stx-producing) E. coli (STEC), pathogens that have been implicated in outbreaks of food-borne illness and can cause intestinal and systemic disease, including severe renal damage. Upon attachment to intestinal epithelium, EHEC generates “attaching and effacing” (AE) lesions characterized by intimate attachment and actin rearrangement upon host cell binding. Stx produced in the gut transverses the intestinal epithelium, causing vascular damage that leads to systemic disease. Models of EHEC infection in conventional mice do not manifest key features of disease, such as AE lesions, intestinal damage, and systemic illness. In order to develop an infection model that better reflects the pathogenesis of this subset of STEC, we constructed an Stx-producing strain of Citrobacter rodentium, a murine AE pathogen that otherwise lacks Stx. Mice infected with Stx-producing C. rodentium developed AE lesions on the intestinal epithelium and Stx-dependent intestinal inflammatory damage. Further, the mice experienced lethal infection characterized by histopathological and functional kidney damage. The development of a murine model that encompasses AE lesion formation and Stx-mediated tissue damage will provide a new platform upon which to identify EHEC alterations of host epithelium that contribute to systemic disease.

Authors

Emily M. Mallick, Megan E. McBee, Vijay K. Vanguri, Angela R. Melton-Celsa, Katherine Schlieper, Brad J. Karalius, Alison D. O’Brien, Joan R. Butterton, John M. Leong, David B. Schauer

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Figure 5

Stx-mediated renal damage during murine infection with C. rodentium (λstx2dact).

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Stx-mediated renal damage during murine infection with C. rodentium (λst...
(A) Renal cytokines in mock-infected mice or mice infected with the indicated strain. Data are pooled from 3 independent experiments. *P < 0.05, **P < 0.01. (B) Micrographs (original magnification, ×600) of H&E-stained kidney sections from mock-infected mice or the indicated infected mice infected at 7–10 days after infection. Arrowheads indicate attenuation and sloughing of epithelial cells within the proximal tubules. Scale bars: 50 μm. (C) BUN of 8-week-old mice, each represented as a single data point, infected with indicated strain or mock infected at day of necropsy (7–10 days after infection). Shown is the pool of 4 independent experiments using 5 mice per group. **P < 0.01. (D) Proteinuria in mock-infected mice or the indicated infected mice. Data shown are average protein indices ± SEM of 5 mice per group. The range of protein measured was 0–500 mg/dl, with 0 indicating undetectable protein, 0.5 indicating trace, 1.0 indicating ~30 mg/dl, 2.0 indicating ~100 mg/dl, and 3.0 indicating ~500 mg/dl. Shown is a representative of 5 independent experiments. *P < 0.05, **P < 0.01 compared with C. rodentium (λstx2dact::kanR). Hematuria in mock-infected mice or the indicated infected mice infected. Shown are the averages (±SEM) of groups of 10 mice. ***P < 0.001 compared with the other groups. Urine Kim-1 concentration in mock-infected mice or the indicated infected mice. Shown are the averages (±SEM) of groups of 3–6 mice. **P < 0.01 compared with the other groups.