Little is known about the role of structure in interactions between different bacterial species during early biofilm formation. In the lab, we use the two bacteria species Pseudomonas aeruginosa and Staphylococcus aureus to probe these interactions. Using optical tweezers to manipulate P. aeruginosa cells, we are able to create patterns with single-cell precision and observe how changes in this initial structure are reflected in the mature biofilm.  This work was published in Langmuir.

Pictures are of a seeded Pseudomonas cluster in a field of Staph at t=0 and t=6 hours after placement of Pseudomonas cells.  Pseudomonas are shown in green and Staph in red.

This work was done by Ph.D. student Chris Rodesney (Physics) and postdoc Jaime Hutchison.

Chris Rodesney took at job at Intel after he graduated from the Gordon group. Jaime Hutchison finished her postdoc and took a job at Solvay.

Another question is how does spatial structure influence the growth and maturation of biofilms. We investigation collaboration with the groups of Rosalind Allen (then University of Edinburgh, now University of Jena), Thomas Bjarnsholt (University of Copenhagen), and Steve Diggle (then University of Nottingham, now Georgia Tech). We found that pre-formed multicellular aggregates can have a growth advantage that arises from the interplay between the spatial structure of the aggregate and the spatial structure of the growth environment. This work was published in mBio.

Visiting Ph.D. student Kasper Kragh (Microbiology, University of Copenhagen) and postdoc Jaime Hutchison used confocal microscopy images, like those above, to monitor the growth of biofilms and determine how it is impacted by pre-existing multicellular aggregates.