Enhanced swarming of bacteria on agar plates containing the surfactant Tween 80

A widely used method for quantifying swarming motility is the swarm plate assay. A significant increase in the motility halo size formed by Escherichia coli or Azospirillum brasilense was measured on Tween 80-containing agar relative to untreated agar. This improvement could benefit the identification of mutants in swarming motility.