Final Report Summary - SABDII (Staphylococcus aureus biofilm dynamics and innate immunity) During this project the interaction of S. aureus biofilms and the human innate immune system was studied. Several in vitro biofilm growth models were set up, both static as well as flow cell biofilm cultures). Using these model systems, the different stages in biofilm development were characterized. For each system and biofilm stage the expression and secretion of immune evasion and immune stimulating molecules was measured. A highly interesting hit from these screenings were the S.aureus Phenol Soluble Modulins (PSMs). These small amphipatic peptides can stimulate the immune cells at low concentrations, but lyse these cells at higher concentrations by creating holes in the cellular membrane. The PSMs were studied in more detail, and their expression in biofilms and inside white blood cells was described in a paper in PlosPathogens (2012) and three follow-up papers in Cellular Microbiology, Infection and Immunity and JoVE (2013). In total 7 papers were published during the duration of the EU-ERG funded project. The setup of the biofilm flow cells in combination with the time lapse fluorescent imaging has resulted in a great opportunity for the fellow. He has established himself as an expert in this field and because of this was approached for several collaborations. One of these collaborations on Neisserial biofilms has already lead to a published Molecular Microbiology paper, with a second in manuscript in progress. The fellow has been able to firmly reintegrate in the Dutch microbiology community. Several collaborations were established with Utrecht University, Leiden UMC, Groningen University, UMCNijmegen. These collaborations resulted in published manuscripts and several more manuscripts in preparation Also a large number of international collaborations was set up, both directly assisting with the research as well as establishing a longer-term professional network essential for successful progression of the fellows career.