Characterization of bacterial swarming motility: a review

Abstract

Swarming motility is a typical synergistic motion, in which bacteria use flagella and Type Ⅳ Pili together to move collectively on semi-solid surfaces. Swarming motility is a hot topic of research in the field of microbiology because of its close relationship with biofilm formation, fruiting bodies formation, pathogen invasion and microbial dispersal and symbiosis. A large number of studies have been conducted on bacterial swarming motility, including changes in the expression of key proteins, changes in chemical communications between bacteria as well as mechanical changes. The expression of flagellin and the level of intracellular c-di-GMP complicatedly regulates the collective behavior of bacteria in colonies, which consequently impacts the swarming motility. The unique physical properties of swarmer cells are conducive to the expansion of the whole colony. Factors such as nutrient and water content in the surrounding growth environment of bacteria also affect the ability of bacteria to swarm to different degrees. It is challenging to construct a universal model of swarming motility based on the molecular mechanisms of swarming in the future.