RT Journal Article SR Electronic T1 Shear force enhances adhesion of Pseudomonas aeruginosa by counteracting pilus-driven surface departure JF bioRxiv FD Cold Spring Harbor Laboratory SP 2023.05.08.539440 DO 10.1101/2023.05.08.539440 A1 Jessica-Jae S. Palalay A1 Ahmet N. Simsek A1 Benedikt Sabass A1 Joseph E. Sanfilippo YR 2023 UL http://biorxiv.org/content/early/2023/05/08/2023.05.08.539440.abstract AB Fluid flow is thought to prevent bacterial adhesion, but some bacteria use adhesins with catch bond properties to enhance adhesion under high shear forces. However, many studies on bacterial adhesion either neglect the influence of shear force or use shear forces that are not typically found in natural systems. In this study, we use microfluidics and single-cell imaging to examine how the human pathogen Pseudomonas aeruginosa interacts with surfaces when exposed to shear forces typically found in the human body (0.1 pN to 10 pN). Through cell tracking, we demonstrate that the angle between the cell and the surface predicts if a cell will depart the surface. We discover that at lower shear forces, type IV pilus retraction tilts cells away from the surface, promoting surface departure. Conversely, we show that higher shear forces counterintuitively enhance adhesion by counteracting type IV pilus retraction-dependent cell tilting. Thus, our results reveal that P. aeruginosa exhibits behavior reminiscent of a catch bond, without having a specific adhesin that is enhanced by force. Instead, P. aeruginosa couples type IV pilus dynamics and cell geometry to tune adhesion to its mechanical environment, which likely provides a benefit in dynamic host environments.Competing Interest StatementThe authors have declared no competing interest.