Grant: Doctoral: Vanier Canada Graduate Scholarships

When we eat food or drink water, we are always at risk of consuming dangerous bacteria such Salmonella, Shigella and types of E. coli. These bacteria cause significant illness in millions of North Americans while the same or similar bacteria sicken or kill millions of children each year in the developing world. All these bad bacteria target the cells that line the insides of our intestines, called epithelial cells, either attaching to, or invading these cells. Therefore most research on these dangerous bacteria has focused on understanding how they infect epithelial cells. However, in order for bacteria to reach these epithelial cells, they must pass through a sticky layer of mucus that lies on top of the epithelium. Surprisingly, although essentially every enteric bacterial pathogen must cross this mucus layer to reach the epithelial cells, we know very little about how this is done, and how dangerous bacteria interact with intestinal mucus. My goal is to use mouse models of bacterial infection to study how bacteria cross the mucus layer. I believe that some bacteria are able to swim through the mucus while others cannot swim, and instead chew up the mucus. I also believe that dangerous intestinal bacteria have evolved strategies to use mucus to help them infect their hosts. I therefore plan to test if bacteria, as they cross the mucus layer, actually use mucus as a binding site, to help them invade epithelial cells. I will also test whether some dangerous bacteria release factors that increase their host production of mucus, as a way to improve their chances of spreading to new hosts, and to remove competing resident intestinal bacteria. Taken together, my studies will improve our understanding of how dangerous bacteria infect our intestines, and examine whether targeting the way bacteria interact with the mucus layer may offer novel opportunities to develop new therapeutics, potentially benefitting the health of both children and adults worldwide.