Dr. Stewart’s research focuses on the control of detrimental microbial biofilms. Biofilms are slimy, multicellular aggregates of bacteria or yeast that form on wetted surfaces. The persistent infections associated with catheters, heart valves, periodontitis (gum disease) and burn wounds are examples of biofilms that affect human health. When microorganisms group together in biofilms they evade killing by antimicrobial agents (disinfectants, antibiotics) that easily kill their free-floating counterparts. Dr. Stewart is interested in the mechanisms that protect microbes in biofilms. These include poor penetration of antimicrobial agents, variation in the physiological activity of microorganisms with biofilms, phenotypic variation, and the activation of stress responses. Dr. Stewart has also investigated alternative strategies for controlling biofilms including anti-biofilm coatings, chemical or enzymatic degradation of the matrix holding the biofilm together, and disruption of cell-to-cell communication.