Dilute Swarmers Have Different Run-and-Tumble Motility Than Planktonic Swimmers

The recent discovery of the peritrichous, swarm-competent bacterium Enterobacter sp. SM3 has offered a new opportunity to investigate the connection between bacterial swimming and swarming. Here we compare the run-and-tumble behavior of SM3 as planktonic swimmers and as swarmers diluted in motility buffer. It was found that planktonic swimmers of SM3 perform a run-and-tumble which is similar to the well-studied species E. coli. In comparison, dilute swamers reduce the frequency of tumbles, resulting in longer run times and shorter tumble angles on average. We also found that planktonic swimmers increase run times and decrease tumble angles in the presence of bulk chemoattractants. These findings serve as a benchmark in determining the connection between swimming, swarming, and the effect of bacterial motility on gut physiology.