Carnegie Mellon University

Catherine Armbruster

Assistant Professor

Department of Biological Sciences
Carnegie Mellon University
4400 Fifth Avenue
Pittsburgh, PA 15213


Catherine Armbuster


Ph.D., Microbiology, University of Washington, Seattle, WA
MPH, Emory University’s Rollins School of Public Health, Atlanta, GA
Postdoctoral Appointment, University of Pittsburgh School of Medicine, Pittsburgh, PA
Postdoctoral Appointment, Geisel School of Medicine at Dartmouth, Hanover, NH


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. Please reach out if you’re curious to hear more or are interested in joining us!


Allison L Haas, Anna C Zemke, Jeffrey A Melvin, Catherine R Armbruster, Matthew R Hendricks, John Moore, Seyed Mehdi Nouraie, Patrick H Thibodeau, Stella E Lee, Jennifer M Bomberger. Iron bioavailability regulates Pseudomonas aeruginosa interspecies interactions through type VI secretion expression. Cell Reports 42 (3), 2023.

Glenn James Rapsinski, Madison Hill, Kaitlin D Yarrington, Allison L Haas, Emily J D'Amico, Catherine R Armbruster, Anna Zemke, Dominique Limoli, Jennifer Bomberger. Pseudomonas aeruginosa senses and responds to epithelial potassium flux via Kdp operon to promote biofilm biogenesis. BioRxiv, 2023.06. 05.543669, 2023.

Catherine R Armbruster, Kelvin Li, Megan R Kiedrowski, Anna C Zemke, Jeffrey A Melvin, John Moore, Samar Atteih, Adam C Fitch, Matthew DuPont, Christopher D Manko, Madison L Weaver, Jordon R Gaston, John F Alcorn, Alison Morris, Barbara A Methé, Stella E Lee, Jennifer M Bomberger. Low diversity and instability of the sinus microbiota over time in adults with cystic fibrosis. Microbiology Spectrum 10 (5), e01251-22, 2022.

C Armbruster, Y Hilliam, S Attieh, A Zemke, C Marshall, J Moore, J Melvin, J Koirala, L Krainz, J Gaston, J Pilewski, S Lee, V Cooper, J Bomberger. 477 Longitudinal population genetics of Pseudomonas aeruginosa isolated from the sinuses, throat, and sputum of adults with cystic fibrosis. Journal of Cystic Fibrosis 21, S271-S272, 2022.

P Zamora, T Reidy, C Armbruster, B Chan, J Koff, P Turner, D Van Tyne, J Bomberger. 415 Bacteriophages that treat Pseudomonas aeruginosa infections induce pro-inflammatory immune responses in the cystic fibrosis airway epithelium. Journal of Cystic Fibrosis 21, S240-S241, 2022.

Arkadiy I Garber, Catherine R Armbruster, Stella E Lee, Vaughn S Cooper, Jennifer M Bomberger, Sean M McAllister. SprayNPray: user-friendly taxonomic profiling of genome and metagenome contigs. BMC genomics 23 (1), 202, 2022.

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