Shear flow patterns antimicrobial gradients across bacterial populations.

Area of Science:

• Microbiology and Biophysics
• Antimicrobial Resistance Research

Background:

• Bacterial populations naturally encounter chemical gradients, but experimental models often lack mechanical relevance.
• Understanding how physical forces influence antimicrobial gradients is crucial for combating resistant pathogens.

Purpose of the Study:

• To investigate the effect of host-relevant shear flow on antimicrobial gradients in Pseudomonas aeruginosa communities.
• To determine how flow influences the interaction between bacterial neutralization and antimicrobial delivery.

Main Methods:

• Utilized microfluidic experiments to simulate shear flow conditions.
• Employed biophysical simulations to model gradient dynamics.
• Visualized single-cell behavior across microfluidic channels.

Main Results:

• Flow patterns significantly altered gradients of hydrogen peroxide, gentamicin, and carbenicillin.
• At low flow, bacteria neutralized antimicrobials; at high flow, delivery overwhelmed neutralization.
• Upstream cells protected downstream cells from antimicrobials, a protective effect diminished by increased flow.

Conclusions:

• Physical flow can enhance antimicrobial effectiveness by increasing delivery and overcoming bacterial neutralization.
• Findings suggest incorporating flow dynamics into antimicrobial discovery, development, and clinical application strategies.