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Pasta of different colors and shapes. © INRA, WEBER Jean

Microbiota and food contaminants: a mycotoxin amplifies the genotoxic effects of intestinal bacteria

Using animal models, INRA researchers and their collaborators1 have been studying the interactions between the bacterial microbiota and a common food contaminant: the mycotoxin deoxynivalenol (DON). They found that the presence of DON enhances the genotoxic effects of certain bacteria. More specifically, it increases the damage caused to the DNA of intestinal cells, contributing to the appearance of cancerous cells. This work raises important questions regarding how potential synergies between food contaminants and the intestinal microbiota could contribute to colorectal cancer development.

Updated on 04/03/2017
Published on 03/23/2017

The human intestinal microbiota contains around 100,000 billion bacteria belonging to very diverse species. A common intestinal resident is Escherichia coli, and E. coli strains form different phylogenetic groups. For example, strains in the B2 group produce colibactin, a genotoxin that damages the DNA of intestinal cells. Recently, it was discovered that B2 strains are becoming increasingly abundant in the intestinal microbiota of people living in industrialized nations.

Fusarium gramineraum, a fungus that produces deoxynivalenol. © INRA, Sylviane BAILLY
Fusarium gramineraum, a fungus that produces deoxynivalenol © INRA, Sylviane BAILLY
Mycotoxins are the most common contaminants of animal feed and human food. Deoxynivalenol (DON) is generated by Fusarium species, which largely infect grain crops. Europeans and North Americans are often exposed to this contaminant via the food they consume. In France and Europe, certain demographic groups, notably children, are exposed to DON at levels that surpass toxicity thresholds.

Using in vitro and in vivo animal models, INRA researchers and their collaborators have been studying how the presence of DON affects the activity of colibactin-producing E. coli.

When animals whose microbiota contain colibactin-producing E. coli are given food contaminated with DON, DNA damage in intestinal cells is far more dramatic than in the intestinal cells of animals without colibactin-producing E. coli. This finding indicates that the presence of DON enhances the genotoxicity of E. coli Group B strains.

These initial results raise questions regarding possible synergies between food contaminants and the intestinal microbiota. The researchers are going to continue investigating the mechanisms underlying DON’s enhancement of the bacteria’s genotoxicity. Indeed, future work plans to address the system’s broader implications, by continuing observations all the way through to the advanced development of colorectal cancer.

1INRA collaborators: INSERM, University of Toulouse III–Paul Sabatier, and ENVT

Contact(s)
Scientific contact(s):

  • Eric Oswald (33 (0)5 67 69 04 17 ) Digestive Health Research Institute (INRA, ENVT, INSERM, University of Toulouse III—Paul Sabatier)
  • Isabelle Oswald (33 (0)5 82 06 63 66 ) Joint Research Unit for Food Toxicology
Press Relations:
INRA News Office (33 (0)1 42 75 91 86)
Associated Division(s):
Animal Health , Microbiology and the Food Chain
Associated Centre(s):
Occitanie-Toulouse

reference

Payros D, Dobrindt U, Martin P, Secher T, Bracarense APFL, Boury M, Laffitte J, Pinton P, Oswald E, Oswald IP. 2017. The food contaminant deoxynivalenol exacerbates the genotoxicity of gut microbiota. mBio 8:e00007-17. doi: 10.1128/mBio.00007-17