Mapping microbial communities during cystic fibrosis lung infection

Cystic fibrosis (CF) is a genetic disorder that is often characterized by chronic bacterial lung infections in affected individuals. Two bacterial species that are often found together in the lungs of people with CF are Pseudomonas aeruginosa and Staphylococcus aureus. People with both P. aeruginosa and S. aureus in their lungs tend to have poorer health outcomes than people with CF who are not colonized by both of these species. It is currently unknown what, if any, interactions between P. aeruginosa and S. aureus contribute to these poorer health outcomes. The focus of my project has been to learn more about different kinds of long chains of sugars, called exopolysaccharides, that are produced and exported out of the cell by P. aeruginosa impact how P. aeruginosa aggregates form by themselves or with S. aureus in the airways of people with CF. We provide evidence for P. aeruginosa-derived exopolysaccharides driving spatial patterning of P. aeruginosa aggregates in CF sputum and driving the fine-scale spatial positioning of P. aeruginosa/S. aureus aggregates in vitro. The results from this study provide evidence of how P. aeruginosa exopolysaccharides may contribute to the observed health decline of people with CF that are coinfected with P. aeruginosa and S. aureus.