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Role of Actinobacillus suis adhesins in host-pathogen interactions in the tonsils of the soft palate of swine

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Title: Role of Actinobacillus suis adhesins in host-pathogen interactions in the tonsils of the soft palate of swine
Author: Bujold, Adina Rachel
Department: Department of Pathobiology
Program: Pathobiology
Advisor: MacInnes, Janet
Abstract: Tonsils are the immune system’s first line of defence against antigens entering the upper respiratory tract. Paradoxically, they are also an important site of colonisation and can be a portal of entry for many pathogens. Despite their significant role, virtually nothing is known about how bacteria attach to or the factors that control invasion of tonsils. To address these questions, I have used the gram-negative facultative anaerobe, Actinobacillus suis, as a model. A. suis is a common resident of swine tonsils, but it sometimes invades the bloodstream, leading to systemic disease and death. Using a combination of bioinformatic and expression studies, I have shown that A. suis expresses different adhesins in growth conditions that mimic the environment of the tonsils and the biofilm and planktonic stages of the bacterium that might lead to host invasion. Three knockout mutants were created to better understand mechanisms of attachment of A. suis to tonsils, and experiments to identify host molecules involved in infection were completed. I found that disrupting adhesins involved in attachment and cell integrity (ompA), attachment to host connective tissues (comE1), and biofilm formation (flp1) resulted in reduced binding of A. suis to purified extracellular matrix components (fibronectin, vitronectin, laminin, collagen I, collagen IV), as well as reduced its ability to form biofilms. Together, these studies provide insight into the pathogenesis of A. suis and other important invasive pathogens known to colonise the tonsils of swine and other species.
URI: http://hdl.handle.net/10214/9646
Date: 2016-05
Rights: Attribution-NonCommercial 2.5 Canada


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Attribution-NonCommercial 2.5 Canada Except where otherwise noted, this item's license is described as Attribution-NonCommercial 2.5 Canada