(275c) Effect of Fluid Induced Shear on Biofilm Accumulation, Erosion and Cell Adhesion of Staphylococcus Aureus

S. aureus infection is a leading public health threat in community and healthcare settings. Its virulence correlates in part with the range of adhesins present on the cell surface, which are known to mediate adhesion to exposed ECM proteins and immobilized platelets in the bloodstream. The ability to form a biofilm then enables the pathogen to evade the host immune system and antimicrobial measures. This study investigates in vitro the potential role of adhesins in the establishment of early S. aureus biofilms under physiologically relevant conditions. We demonstrate with immunocytometry and kinetic studies that eroding planktonic cells and fixed sessile cells retain significant adhesion properties with respect to ECM proteins over 24 hours of biofilm growth. Our data reveal a potential mechanism for the promotion of secondary sites of infections via adhesin-mediated binding events. Immunofluorescent confocal microscopy is used to characterize the architectural attributes of S. aureus biofilms in situ. Results show that volumetric and areal parameters such as biovolume and cluster perimeter level off with increased shear while textural parameters and others including fractal dimension and porosity tend to be shear-dependent over the fluid shear range investigated. Taken together, our findings reveal important biophysical properties of staphylococcal biofilms grown under fluid shear stress and suggest potential therapeutic approaches for the treatment of staphylococcal infections.