Buret, AndreBeatty, Jennifer2015-09-042015-11-202015-09-042015Beatty, J. (2015). The Impact of Giardia duodenalis on Human Intestinal Microbiota Biofilms: A Role in Chronic Post-infectious Gastrointestinal Disease Development? (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/28181http://hdl.handle.net/11023/2432Irritable Bowel Syndrome (IBS) represents a common cause of altered gastrointestinal function seen in individuals throughout the developed world. Despite its prevalence, the pathophysiological mechanisms underlying IBS remain incompletely characterized. Numerous reports indicate post-infectious IBS (PI-IBS)-symptoms in upwards of 36% of patients previously subject to acute enteric infections. Distinct differences in the species distribution of the microbiota of IBS patients are well documented. On the other hand, disruptions in the microbiota structure, which normally exists as a series of biofilm communities, have yet to be analyzed in the context of IBS pathophysiology. Considering PI-IBS, it is inherently important to examine the possibility that disease pathogenesis may be determined by a pathogen-mediated disruption in the homeostatic function of the resident intestinal microbiota. Giardia duodenalis infections (giardiasis) represent a highly prevalent cause of acute diarrheal disease in symptomatic patients, worldwide. Recent outbreaks in Italy and Norway have elucidated a link between inititial Giardia infection, and subsequent development of PI-IBS symptoms in many patients. Giardia represents a novel model that can be used to study the complex polymicrobial interplay that occurs between a pathogen and the resident intestinal microbiota, while also providing insight into the mechanisms thorugh which chronic gastrointestinal disturbances, such as PI-IBS, are initiated. Additionally, much of our understanding of the role of the microbiota in PI-IBS has come from studies focusing on populations collected from fecal samples, or single species, and therefore not entirely representative of the host microbiota composition and biofilm structure. Consequently, an in vitro model system that encompasses the complex community structure, and species distribution of the mucosal mibrobiota, used in concert with an infection model through which poly-microbial interactions can be assessed, represents an important tool in understading the early initiation events underlying PI-IBS development. This work employed the use of a novel model system, representative of the human resident intestinal microbiota, to characterize the impact of G. duodenalis on intestinal microbiota biofilms. Collectively, our findings illustrate the consequences of polymicrobial interactions that occur during acute enteric infection, and offer insight into the mechanisms leading to post-infectious chronic gastrointestinal disorders, such as PI-IBS.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.MicrobiologyIrritable Bowel SyndromeMicrobiomeGiardia duodenalispolymicrobialdoctoral thesis10.11575/PRISM/28181