Dynamics of microbe-microbe and microbe-host interactions in mixed-species biofilm infection

Bacteria often produce a sticky coat in order to glue themselves together into multicellular structures called biofilm. Biofilms are found in industrial settings (like liquid handling systems in factories) and in many chronic infections (like lung infections in people with cystic fibrosis, or diabetic foot ulcers). The biofilm coating allows bacteria to stick to surfaces and can prevent antibiotics and immune cells from reaching the bacteria to kills them. Also, biofilms are often a response to very specific environmental conditions that also change bacterial physiology. Bacteria in biofilms may express different genes and have quite different metabolism from bacteria growing as single, freely-moving cells in standard lab broth. These physiological changes can also increase the bacteria's resistance to antibiotics, and also allow different strains and species of bacteria to coexist and cooperate to protect one another from antibiotics. If we want to understand how bacteria behave in biofilms and why this makes them so hard to get rid of, we need laboratory models of the specific contexts in which bacteria from biofilms. These will allow us to study diverse biofilm communities of bacteria in an environment that is chemically and structurally similar to a real-world setting in which biofilms cause problems. In this PhD, I will use a model of bacterial biofilms in the lungs of people with cystic fibrosis to improve our understanding of the fundamental microbiology of bacterial biofilm formation, ecology and antibiotic resistance. I use pigs' lungs, supplied by a local butcher as a by-product of the meat industry, and carefully-constructed artificial CF lung mucus to mimic the lung environment. I will study how key species of bacteria interact and evolve in these biofilms, and assess how models like mine could be used to find better ways of dismantling biofilm.