A shear-induced limit on bacterial surface adhesion in fluid flow.

Area of Science:

• Microbiology
• Fluid Dynamics
• Biophysics

Background:

• Bacterial surface adhesion and biofilm formation pose significant challenges in medical and industrial fluid systems.
• Effective control strategies require a deep understanding of bacterial transport mechanisms near surfaces.

Purpose of the Study:

• To theoretically investigate the interplay between bacterial motility and fluid flow in influencing bacterial surface adhesion.
• To systematically derive bacterial diffusivity near surfaces and determine adhesion rates.

Main Methods:

• Utilized a hybrid asymptotic-computational approach to model bacterial transport.
• Exploited the velocity difference between fluid flow and bacterial swimming.
• Derived coarse-grained bacterial diffusivity as a function of swimming speed, rotational diffusivity, and shape.

Main Results:

• An analytical upper bound for the bacterial adhesion rate was calculated assuming irreversible adhesion.
• The study predicts maximal bacterial adhesion at intermediate fluid flow rates.
• At lower flow rates, adhesion increases with flow; at higher rates, shear-induced reorientation reduces adhesion.

Conclusions:

• Bacterial adhesion is a complex process influenced by both intrinsic bacterial properties and external fluid dynamics.
• Understanding these interactions is crucial for developing targeted strategies to prevent unwanted bacterial surface colonization.
• The findings provide a theoretical framework for optimizing fluid system designs to minimize bacterial adhesion.