Abstract of talk

The complex interplay between the natural bacterial communities colonising the gut environment and the human host have evolved through millions of years of co-evolution. A multitude of scientific studies have revealed the important role of the gut microbiota in states of both health and disease and highlighted that changes in the resident microbial ecosystem may represent a risk factor. For this reason, it is important to consider the human microbiome in a chemical risk assessment, with an emphasis on elucidating any microbiota-disrupting effects that may be associated with exposure.
Clearly, some compounds (such as antibiotics) have a large capacity to disturb the natural ecosystem within the gut environment, which has been linked to long-term health effects. Other compounds may have putative effects, due to a specific mode-of-action known to be associated with microbial pathways, while still other compounds overall can be considered inert in terms of effects on the natural microbiota. In this talk, examples from animal trials conducted in our research group and representing the three above scenarios will we presented and discussed. Specifically, I will discuss exposure to beta-lactam antibiotics, the widely used herbicide glyphosate, and the anthropogenic fluorosurfactant perfluorooctanesulfonic acid (PFOS).
It is important to appreciate that many natural food ingredients and dietary choices will affect the intestinal bacterial composition. This means that risk assessments of chemical compounds towards the microbiota cannot solely be based on observed changes of the gut microbiota structure or function, as not all changes are bad. I will present considerations for future guidance on this issue, including tools, markers and end-points to assess actual microbiota disruption, defined as induced changes in microbiota composition and/or activity that can cause a detrimental effect on health.
While chemical compounds may disrupt the microbiota, the microbiota may also affect the degradation and absorption of chemical compounds entering the gut environment. Data will be presented on how antibiotic-induced microbiota disturbances may affect overall systemic exposure to chemical compounds exemplified by PFOS exposure.