PhD thesis of Sheiam Sulaeman (2008-2011)

Campylobacter is known to be the major cause of bacterial foodborne illness worldwide. As a foodborne microaerophilic micro-organism, this pathogen can survive transitionally throughout the food processing, surpassing the lethal ambient air. Consequently, this pathogen has to develop adaptation strategies to reach the human gut. In this study, we have explored adaptation strategies of Campylobacter by testing its capability to adhere to inert surfaces and also the role of membrane proteins under oxidative conditions. Using an innovative technique, we have demonstrated a high intra and inter-species variability in the adhesion capability to inert surfaces of Campylobacter. Different adhesion capability was also observed as a function of the environment with a higher adhesion in oxydative conditions. A subproteomic analysis on each of the two membrans of C. jejuni indicated that some proteins involved in adhesion to biotic and abiotic surfaces and in virulence were over-expressed. Finally, an additional study of the membrane complexome, using 2D-BN/SDS-PAGE, identified functional entities involved in the molecule transport and the virulence of C. jejuni.Taken together, these data indicate that this pathogen modifies its biological and physiological characteristics in the conditions out of its natural habitat which favours its persistence in food environment sensu lato and enhance its virulence factors.