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Dissertation Defense Announcement

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Madame Anaïs Cazals

Will publicly defend her PhD work entitled

Study of the impact of host genetics and gut microbiota composition on Salmonella Enteritidis carriage in mice and chickens

supervised by Fanny Calenge and Jean Jaubert

Defense scheduled for Thursday December 9th at 14.00

Jury Composition

• Binnaz Yalcin, INSERM – NeuroGeMM, Reporter and examinator
• Hélène Gilbert, INRAE – Genphyse, Reporter and examinator
• Olga Soutourina, Université Paris-Saclay, Examinator
• Daniel Vaiman, INSERM, Examinator
• Sylvie Combes, INRAE – Genphyse, Examinator
• Fanny Calenge, INRAE – GABI, PhD Advisor
• Jean Jaubert, Institut Pasteur, PhD Co-Advisor

Abstract

Salmonella enterica Enteritidis (SE) is one of the major human food poisoning causes through the consumption of contaminated poultry products (meat and eggs). This bacterium is carried asymptomatically by chickens, but it is able to infect humans and cause diseases. Genetic selection and intestinal microbiota modulation are two promising ways to reduce its carriage in chickens and hence its spread in poultry farms. The objectives of this thesis are to identify the main genetic and microbial factors controlling individual Salmonella carriage in two experimental models. The "chicken" model was used to study the impact of the genetic background on the resistance and microbiota composition of young individuals post SE infection. Analyses of caecal microbiota composition and gene expression in caecal tonsils were conducted and led to the identification of intestinal bacteria (e.g. Christensenellaceae), differentially expressed genes (e.g. Fut2) and signalling pathways (e.g. short-chain fatty acid pathway) associated with the response to the infection. A significant impact of the line on microbiota composition was also identified. The "mouse" model was used to identify host genomic regions controlling chronic SE carriage. Two genetic reference populations, the Collaborative Cross (CC) strains and the Diversity Outbred (DO) mice, allowed the identification of new QTl (Ses11 to Ses17) and candidate genes such as Lingo2 or Btnl4 associated with the response to SE infection. In CC strains, we showed a high diversity of bacterial loads in liver and spleen, allowing the identification of strains with extreme phenotypes to SE, either susceptible (e.g. CC009/Unc) or resistant (e.g. CC024/GeniUnc), that could be used as new experimental models. This project has therefore allowed the identification of new mechanisms associated with the response to SE infection thanks to the use of two complementary experimental models.

Practical Information

The PhD defense will be held on Thursday December 9th at 14.00 in Building 440's lecture hall at INRAE Jopuy-en-Josas (limited number of seats). You may follow the defense either live or via video conferencing. If you would like to see the defense live, please contact Anais Cazals.