The evolution of bacterial resistance to the Type 6 Secretion System

The bacteria that normally live inside us play an important role in protecting us from infection. However, some pathogens can bypass this defence, by secreting toxins which eliminate our protective bacteria. It is not currently known whether protective bacteria can evolve resistance to pathogens' toxin cocktails, and thereby block infection. I will use a combination of laboratory experiments and computer modelling to study the evolution of toxin resistance in a common protective bacterium, Escherichia coli. I will investigate when and how resistance occurs, and how this depends on the number and types of toxin being secreted. I will also examine whether pathogens can in turn evolve to overcome resistance. My research will advance understanding of how bacteria evolve to resist pathogen attack, and thus protect hosts from pathogen infection.