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THE MODULATION OF THE HUMAN INTESTINAL MICROLFORA COMPOSITION AND STRUCTURE BY CAMPYLOBACTER JEJUNI
S Akierman, J Beatty, P Beck, K Rioux, A BuretUniversity of Calgary, Calgary, AB
Aims: Campylobacter jejuni (C. jejuni) is the worldwide leading cause of human bacterial enteritis. There is recent evidence that indicates that acute gastroenteritis may contribute to the production of post-infectious symptoms in patients with inflammatory bowel disease (IBD). While the postulated causes of IBD are various, evidence suggests a role of modulation of the intestinal microflora in the pathophysiology. There is currently a lack of knowledge as to whether the exposure to enteropathogens may lead to an imbalance amongst the gastrointestinal microflora thus prompting an inappropriate immunological response, leading to the development of IBD. Our study served to investigate whether C. jejuni is capable of modulating the human intestinal microflora biofilms generated from colonic biopsies.
Methods: Mucosal biopsies of the colon were obtained from healthy donors undergoing screening colonoscopy. Homogenates of the biopsies were used to seed anaerobic biofilms in the Calgary Biofilm Device. The resulting multispecies bacterial biofilms were then exposed to live C. jejuni and assessed by viable cell counting, XTT assay, terminal restriction fragment length polymorphism (T-RFLP), confocal scanning laser microscopy (CSLM), and scanning electron microscopy (SEM).
Results: CSLM imaging of the biofilms demonstrated a decrease in biofilm thickness when exposed to C. jejuni. Additionally, SEM demonstrated a reduction in the extracellular matrix of the multispecies biofilms when exposed to C. jejuni. At the same time, viable cell counts showed C. jejuni adheres with the microflora biofilms. Lastly, data obtained from T-RFLP showed an increase in the order Clostridiales relative growth when exposed to C. jejuni.
Conclusions: Our preliminary results indicate a C. jejuni induced thinning of cultured multi-species biofilm as well as a modification in the microbial representatives polysaccharide expression. Moreover C. jejuni modulates the multi-species biofilms composition by increasing the relative growth of Clostridiales. We postulate that these findings may play an important role in the development of symptoms in susceptible patients with IBD as well as the pathogenesis of campylobacterosis and suggests a need for additional investigation.