Improving the reproducibility of Pseudomonas aeruginosa swarming motility assays.

Swarming motility is a rapid and coordinated migration of a bacterial population across a semi-solid surface. This multicellular phenomenon is getting increasing attention as it is suspected to be related to biofilm development of Pseudomonas aeruginosa. Published swarm plate preparation protocols differ greatly from one study to another and no reproducible and standardized protocols have been proposed to accurately study this phenomenon. We report here a rapid and highly reproducible swarm plate protocol for P. aeruginosa and show how different key parameters affect this type of motility (i.e. agar %, drying time under laminar flow, incubation temperature and pH). Results reported here will help to standardize swarming motility assays and develop effective swarm plate protocols for other bacterial species.