1. Prof. Erica Hartmann

The built indoor environment is enriched for antibiotic-resistant pathogens compared to natural outdoor environments. In our quest to diminish the number of viable antibiotic-resistant pathogens indoors, with the ultimate goal of halting the spread of infectious disease, we have created an arsenal of antimicrobial chemicals, which we now embed in various materials and use in countless cleaning and personal care products. Regardless of where we put these chemicals, they can have unintended consequences on indoor microbes by changing the structure of indoor microbial communities or selecting for certain functions, including antibiotic resistance. Their use further complicates subsequent efforts in resource recovery, e.g., in greywater reuse. Using molecular and traditional microbiology techniques, my lab assesses whether antimicrobial chemicals are indeed associated with decreased microbial viability. Our work focuses on undomesticated, non-model organisms to observe responses of authentic microbial communities. Using synthetic microbial communities and microcosm experiments, we probe causal relationships between exposure to antimicrobial chemicals and the development of different resistance phenotypes and genotypes. We evaluate whether exposure to antimicrobial chemicals is associated with outcomes including enrichment for antibiotic resistance genes, as well as phenotypic responses like sporulation and biofilm formation. We also use analytical chemistry techniques to track the fate and transport of antimicrobial chemicals. Together, this work provides a window into microbe-chemical interactions transpiring within buildings and in engineered systems for resource recovery, giving us knowledge we need to make better design choices.