Catherine Armbruster

Bacteria constantly evolve in response to specific selective pressures in their environment. When opportunistic pathogens initiate an infection, they draw upon a genetic repertoire that was shaped by the environment where they resided prior to infection. For many infections, the prior environment is the built environment—the infrastructure of our homes, hospitals, schools, workplaces, and other buildings. Potable water is a major source of opportunistic pathogens that cause life-threatening infections in immunocompromised people, with a yearly US economic burden of $2.4 billion dollars. Biofilms ubiquitously coat surfaces within building premise plumbing (e.g. water pipes, faucets, shower heads); however, little is known about the microbial ecology and evolution of this niche. Biofilms are a physiologically distinct, aggregative lifestyle in which bacteria are encased in a matrix that provides not only protection, but spatial structure (biogeography), nutritional and chemical gradients, and opportunities for cell-cell interactions. Biofilms are similarly recalcitrant during infection of diverse host sites, yet therapeutic strategies to prevent or eradicate biofilm infections are currently lacking.

The Armbruster Lab uses bacterial genetics, host-pathogen model systems, and evolutionary genomics approaches to investigate how bacteria in biofilms persist in the built environment and transition into the host to establish chronic infections. We are currently investigating how opportunistic pathogens, including Pseudomonas aeruginosa, evolve in polymicrobial biofilms in potable water and how this evolutionary history impacts downstream host-pathogen interactions in cystic fibrosis (CF) respiratory infections and antimicrobial resistance. We also use experimental evolution to identify traits important for persistence of P. aeruginosa and other opportunistic pathogens in CF airways. Our goal is to identify public health, engineering, or therapeutic strategies to prevent and treat opportunistic infections from the built environment. We believe emphatically that diversity, kindness, and inclusivity are critical to nurturing an innovative and intellectually fulfilling environment in our laboratory.