Swarming Behavior of Pseudomonas aeruginosa Under Antibiotic Stress

Place an agar plate onto a printed template to align the center and six evenly spaced satellite spots.

Spot a healthy Pseudomonas aeruginosa culture at the center of the plate.

Place a mixture of the same culture with an antibiotic onto the satellite spots.

Cover the plate with a black lid to reduce light reflections.

Place it on a scanner inside an incubator with a constant temperature and humidity to maintain bacterial growth.

Healthy bacteria at the center grow and spread outward in tendril-like swarming patterns that radiate across the agar surface.

Bacteria mixed with the antibiotic undergo stress and release chemical signals that diffuse through the agar.

As the swarm reaches these zones, it senses the stress signals.

This triggers an avoidance response, redirecting bacterial growth away from the antibiotic-exposed regions.

Time-lapse imaging shows bacterial growth and changes in swarm expansion under antibiotic stress.

For swarming agar plating, hold a P20 pipette tip loaded with five microliters from an overnight P. aeruginosa culture at a 10-45 degree angle 2-1/2 centimeters above the center of one swarming plate and depress the plunger to the first stop touching the agar with only