Bacterial Biofilms: Fast and Slow Streamers
Unwanted, harmful bacterial cells can be found fouling surfaces everywhere from lifesaving medical devices to toe-jamming pond scum — often in the form of “biofilms,” where they clump together into a slimy, protective surface. In recent years, many researchers have been exploring the physics behind biofilm formation and trying to figure out better ways mitigate the problem or to prevent the fouling films from forming in the first place.
Howard Stone and his colleagues at Princeton are exploring the mechanics and molecular biology of one biofilm-related phenomenon known as streamer formation. When biofilms grow and develop in the presence of fluid flow, they form three-dimensional thread-like offshoots made of polymers and cells. These “streamers” can rapidly clog small channels and quickly foul sanitary surfaces.
Last year, Knut Drescher, a postdoc in Stone’s laboratory, took videos of fluorescent bacterial streamers, showing how they can completely clog microfluidic channels, which mimic natural systems and medical devices, over a period of tens of hours. In Denver, new work by Stone’s graduate student Kevin Minyoung Kim compares biofilm streamer formation in two common bacterial pathogens that both cause severe illness in humans: Pseudomonas aeruginosa and Staphylococcus aureus, the culprit behind MRSA infections.
“Surprisingly, S. aureus forms the streamers MUCH more rapidly,” Stone said. “We do not understand why, but it certainly raises significant questions about what material/biological features of the bacteria and biofilm set the time scale for formation of the three-dimensional streamers.”
