Screening of Cytotoxic B. cereus on Differentiated Caco-2 Cells and in Co-Culture with Mucus-Secreting (HT29-MTX) Cells.

is an opportunistic foodborne pathogen able to cause diarrhoea. However, the diarrhoeal potential of a strain remains difficult to predict, because no simple correlation has yet been identified between the symptoms and a unique or a specific combination of virulence factors. In this study, 70 strains with different origins (food poisonings, foods and environment) have been selected to assess their enterotoxicity. The cell-free supernatants have been tested for their toxicity in vitro, on differentiated (21 day-old) Caco-2 cells, using their ATP content, LDH release and NR accumulation. The genetic determinants of the main potential enterotoxins and virulence factors (, , , , , , , and ) have also been screened by PCR. This analysis showed that none of these genes was able to fully explain the enterotoxicity of strains. Additionally, in order to assess a possible effect of the mucus layer in vitro, a cytotoxicity comparison between a monoculture (Caco-2 cells) and a co-culture (Caco-2 and HT29-MTX mucus-secreting cells) model has been performed with selected supernatants. It appeared that, in these conditions, the mucus layer had no notable influence on the cytotoxicity of supernatants.