High-fibre diets and E. coli infection

Consuming diets higher in fibre may increase the risk for Escherichia coli O157:H7 infection and severe disease according to a new study, ‘Dietary choice affects Shiga toxin-producing Escherichia coli (STEC) O157:H7 colonisation and disease’, published in the online Early Edition of The Proceedings of the National Academy of Sciences, 20 May.

Scientists from the Uniformed Services University of the Health Sciences (USU) demonstrated that mice fed high-fibre diets (HFD) had elevated levels of intestinal butyrate which - although a beneficial gut metabolite - enhanced the gut-binding capacity of Shiga toxin made by the foodborne bacterium E. coli O157:H7.

The study showed that the amount of gut bacteria in HFD-fed mice increased while the per cent of commensal Escherichia species decreased compared to gut bacteria in mice fed a low-fibre diet (LFD).

These changes led to higher E. coli O157:H7 colonisation levels, more weight loss and greater rates of death in HFD-fed than in LFD-fed STEC-infected mice.