Join the Department of Chemical and Biological Engineering for a spring seminar on Wednesday, January 24 from 3:15–4:30 p.m. in Perlstein Hall Auditorium. The seminar, titled “Biofilm Infections on Medical Devices,” will feature Philip Stewart, professor of chemical and biological engineering, Center for Biofilm Engineering, Montana State University.

Bacteria that colonize the surface of indwelling medical devices such as catheters or prosthetic joints can establish slow-moving yet persistent infections.  Once the microorganisms form a biofilm, they become protected from killing by antiseptics, antibiotics, and the body’s innate immune defenses.  Protective mechanisms in biofilms include incomplete antimicrobial penetration and dormancy of a subpopulation of microbials cells.  Both mechanisms derive from reaction-diffusion interactions that are amenable to engineering analysis.  Because established biofilms are so recalcitrant to chemotherapy, approaches to preventing biofilm formation are sought.  An alternative and still unexplored strategy is to guide or boost the host defenses around the implanted device to eliminate contaminating bacteria.  This strategy is partly inspired by recent stunning progress with immunotherapeutic approaches for treating cancer.  To investigate the factors that govern immune cell efficacy on an abiotic surface, the ability of human neutrophils to clear newly attached S. aureus bacteria from a serum-coated glass surface was examined in vitro using time-lapse confocal scanning laser microscopy and quantitative image analysis.  Results show that the ratio of the surface concentrations of neutrophils and bacteria as well as the time required to recruit neutrophils to the surface are critical parameters affecting the potential of host defenses to eradicate nascent biofilm. Ultimately such research could lead to a new generation of immunomodulatory biomaterials that direct and enhance the ability of innate immune cells to prevent infections associated with implanted medical devices.

Stewart is a professor of chemical and biological engineering at the Center for Biofilm Engineering at Montana State University with degrees in Chemical Engineering from Rice University and Stanford University. His research focuses on the control of detrimental microbial biofilms and strategies for preventing biofilm infections. Stewart has been integrally involved with the Center for Biofilm Engineering since his arrival on the Montana State campus, serving as director from 2005–15.