(5dh) Quantitative Analysis of the Effects of Hydrodynamic Shear on the Textural and Areal Parameters of S. Aureus Biofilms

S. aureus infection is a leading public health threat in community and healthcare settings and has been shown to develop in natural habitats within aggregated biofilms. During infection, initial cell attachment, biofilm growth and maturation, and cell detachment are decisive steps that affect the virulence and the pathogenicity of that organism. The biological, chemical and physical nature of S. aureus biofilms grown under hydrodynamic conditions is a critical determinant of persistence, recurrence, and metastatic spread demonstrated by this pathogen. The purpose of this study was to characterize the biophysical properties of early S. aureus biofilms grown under physiologically relevant shear rates ranging from 50 to 500 s^-1. Immunofluorescent confocal microscopy provided a basis for the quantitative analysis of the architectural attributes of S. aureus biofilms in situ. Volumetric and areal parameters such as biovolume and cluster perimeter leveled off with increased shear while textural parameters and others including fractal dimension and porosity were shear-dependent over the fluid shear range investigated. Taken together, our findings highlight the effects of fluid shear stress on the biophysical properties of staphylococcal biofilms.