Dynamic switching enables efficient bacterial colonization in flow

Abstract

Bacteria colonize environments that contain networks of moving fluids, including digestive pathways, blood vasculature in animals, and the xylem and phloem networks in plants. In these flow networks, bacteria form distinct biofilm structures that have an important role in pathogenesis. The physical mechanisms that determine the spatial organization of bacteria in flow are not understood. Here, we show that the bacterium colonizes flow networks using a cyclical process that consists of surface attachment, upstream movement, detachment, movement with the bulk flow, and surface reattachment. This process, which we have termed dynamic switching, distributes bacterial subpopulations upstream and downstream in flow through two phases: movement on surfaces and cellular movement via the bulk. The model equations that describe dynamic switching are identical to those that describe dynamic instability, a process that enables microtubules in eukaryotic cells to search space efficiently to capture chromosomes. Our results show that dynamic switching enables bacteria to explore flow networks efficiently, which maximizes dispersal and colonization and establishes the organizational structure of biofilms. A number of eukaryotic and mammalian cells also exhibit movement in two phases in flow, which suggests that dynamic switching is a modality that enables efficient dispersal for a broad range of cell types.

Ultrasound‐assisted swelling of bacterial cellulose

“…An attractive feature of the BC is the possibility to create cellulose with a desired fibre structure at both macroscopic and nanoscopic scales in the process of the material formation, rather than using post-production treatment methods. Along with chemical and biological processes which affect the biofilm development, hydrodynamic flows in bacterial suspensions are also capable of shaping biofilms 14 . It has been recently demonstrated that when suspensions of E. coli are perturbed by surface waves, patterned biofilms at the liquid-solid interface are developed 15 .…”

The effect of flow on swimming bacteria controls the initial colonization of curved surfaces

“…Biofouling and biocorrosion are ubiquitous, costly problems also in other settings, from industrial wastewater systems to marine environments 5,6 . To date, the mechanistic understanding of bacterial colonization of surfaces mainly focused on flat surfaces [7][8][9][10][11][12] ; yet in many applications surfaces are not flat. As a result, no general framework exists to account for the role of surface shape on bacterial colonization.…”

Biofilms 2018: a Diversity of Microbes and Mechanisms

“…Using a microfluidic device and P. aeruginosa as a model, cyclical events of attachment, detachment, and reattachment were observed, interspersed with periods of movement on the surface or within flow. This dynamic switching was proposed to maximize the spreading of the bacteria (45). Fluorescence lifetime imaging microscopy (FLIM) and spatial and temporal resolution with NADH as a metabolic marker revealed that surface attachment increases the levels of free NADH.…”