Effect of α-Hemolysin Producing E. coli in Two Different Mouse Strains in a DSS Model of Inflammatory Bowel Disease.

BACKGROUND

Phylogroup B2 Escherichia coli have been associated with ulcerative colitis (UC). In this study, we aimed to compare colonization with the UC-associated E. coli p19A in different mice strains, to investigate the role of alpha hemolysin in a UC mouse model.

METHODS

In this study, Sigirr -/- and C57BL/6 mice were chosen, and UC was induced by adding dextran sulfate sodium (DSS) to the drinking water. The mice were pre-treated with ciprofloxacin. p19A expressing luminescence and GFP, alpha-hemolysin knock out p19A-ΔhlyI II, and non-pathogenic lab E. coli DH10B were cultured in LB broth, and orally gavaged into the mice. Colonization with p19A WT was visualized using an in vivo imaging system.

RESULTS

p19A WT colonized the colon, ileum, Peyer's patches, liver, and spleen of infected C57BL/6 and Sigirr -/- mice. A total of 99% of the p19A WT infected C57BL/6 mice and 29% of the p19A WT infected Sigirr -/- mice survived to the 4th post infection day.

CONCLUSION

UC-associated E. coli p19A WT colonized the intestines of DSS-treated mice and caused extra-intestinal infection. Hemolysin is an important factor in this pathogenesis, since isogenic hemolysin mutants did not cause the same inflammation.