Microbial toxins are primary virulence factors to many foodborne pathogens. Formed toxins can exist independently from their microorganism at the moment of consumption, i.e. the pathogen may be inactive, while the toxin is still biologically active. They can be also expressed in the human gut and play a key role in foodborne infections and host pathogen interactions. In this session three pathogens will be considered, Bacillus cereus, Enterohemorrhagic Escherichia coli, and Staphylococcus aureus. For B. cereus, an underlying hypothesis is that production of microbial toxins in food usually occurs in low doses, which do not result in immediate, visible, intoxication symptoms. Exposure to mixtures of toxins (and other contaminates) requires better understanding. There is a major knowledge gap regarding exposure and modes of action.

In this session, we will elaborate on: the effects of B.cereus emetic toxin and related depsipeptide mycotoxins, found in the same cereal-based foods, on human intestinal and liver cells; the finding that B. cereus and S. aureus, often found in the same foods, can simultaneously produce respective toxins when no other background flora is present; an that protective microbe-microbe interactions between S. aureus and native lactic acid bacteria result in metabolic shifts, which prevent enterotoxin production. Using an in vitro model of the human large intestine, we will, also, look at survival of an EHEC in simulated human colonic conditions and investigate the effect of probiotic treatments under abiotic and biotic parameters of the human gut. For this purpose, three presenters will show multifaceted aspects of microbial toxins, virulence factors, and host-pathogen interactions by sharing data generated by different omics techniques, including transcriptomic, virulomic and functionomic assessments of microbe-microbe-host interactions.

Presentations