Title of the presentation:
Contribution of the gut microbiota to infectious and pediatric inflammatory bowel diseases.

Biography:
MSc. Universite Louis-Pasteur 1992
PhD. Universite Louis-Pasteur 1997

Short summary of research interests:
Our current research seeks to identify how human pathogens colonize the host gastrointestinal tract. We are not solely looking at the pathogen level but are also trying to understand the interplay of the pathogen, the endogenous gut microbial community as a whole, and the host. While classical microbiology seeks to understand the function of a gene or a few groups of genes from one single organism, our research aims to elucidate the role of all the genes and how they relate to one another from an entire microbial community. In particular, our research seeks to understand the dynamic interactions between the different components of the gut environment upon the stressful colonization and invasion by a pathogen in order to create a detailed picture on how a pathogen operates.

Abstract:
The intestinal microbiota is composed of a complex and dynamic population of microorganisms. Members of the gut microbiota play a key role in maintaining human health and well being by contributing to the host defense (pathogen protection), the maturation of the immune system, providing nutritional functions to the host, and by affecting gut development. We have found that the human pathogen Campylobacter jejuni significantly benefits from the functionality of the gut microbiota by scavenging essential nutritional elements made available by other bacterial species. Mass-spectrometry analyses of mucins from a porcine pathogenic and a chick commensal model of C. jejuni suggest a possible mechanism by which C. jejuni switches from a commensal to a pathogenic relationship. In addition to inadvertently promoting infectious disease, we also found that the gut microbiota is a key factor in the etiology of pediatric inflammatory bowel disease (IBD). Surveying the gut microbiota composition by 16S rDNA pyrosequencing and metaproteomic analysis of the host-microbiota interactions led us to several key discoveries that indicate an alteration of the host and gut microbiota cross-talk in pediatric IBD. Our data suggest that the gut microbiota as a whole might act as a surrogate pathogen by triggering and/or maintaining inflammation.

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