Campylobacter jejuni is the most common pathogen among foodborne bacterial infections in Europe, with over 200,000 cases reported at an estimated cost of 2.4 billion euros per year. This bacterium is found mainly on poultry meat during evisceration. It has the ability to activate mechanisms that allow it to resist and therefore persist throughout the implementation of agri-food processes. To develop prevention strategies, it is useful to better understand this pathogen and its adaptation mechanisms. One of the key stages associated with the adaptation of bacteria is the passage from the exponential phase of growth to the stationary phase. Molecular mechanisms driving this transition in many bacteria are not present in C. jejuni.
By comparing the proteome (technique used 2D-SDS-PAGE) and the expression of genes (technique used qRT PCR) in exponential phase and in stationary phase of growth of C. jejuni, a regulatory factor called CosR, overexpressed in stationary phase, has been highlighted. The transient increase in the number of CosR transcripts during the transition from the exponential phase to the stationary phase could be at the origin of a negative autoregulation of the gene encoding this regulator. It was shown in this study that the CosR protein binds to its own promoter region, confirming this hypothesis. Bioinformatics analyzes carried out on the complete genome of several strains of C. jejuni have made it possible to refine the consensus DNA binding sequence of this protein in the promoter region of these genes. This work now consists of determining the regulon of CosR in order to understand the metabolic pathways controlled by this protein in the stationary phase.

Partners : this work was carried out in collaboration with the University of Chemistry and Technology of Prague in the framework of the European project Cost BacFoodNet and the project Hubert Curien SARPAC.