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The human intestinal microbiote contains more than 100 000 billion bacteria of huge diversity. Escherichia coli, one of them, is very common and has different groups. The E. colibacteria of group B2 produce a genotoxic substance, called colibactin, that produces DNA damages in intestinal cells. Nowadays, there is an increase in the B2 group bacteria in the intestinal microbiota of industrialized countries populations.

• Researchers of Toxalim's E5-BioToMyc team (Biosynthesis & Toxicity of Mycotoxins) and their partners (Inserm, Toulouse 3 University, Toulouse Veterinary College) studied the consequences of the simultaneous presence in the intestine of E. coli B2 bacteria of microbiota and the mycotoxin, deoxynivalenol (DON), a common food contaminant.

• They show that the presence of this mycotoxin reinforces the genotoxic character of the bacteria, i.e. increases the number of breaks on the DNA strands in intestinal cells, a phenomenon which can lead to the appearance of cancer cells.

This work raises in particular the question of the synergy between food contaminants and intestinal microbiota with respect to the process of colorectal carcinogenesis.