Direct upstream motility in Escherichia coli

Tolga Kaya, Hur Koser*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

116 Citations (Scopus)


We provide an experimental demonstration of positive rheotaxis (rapid and continuous upstream motility) in wild-type Escherichia coli freely swimming over a surface. This hydrodynamic phenomenon is dominant below a critical shear rate and robust against Brownian motion and cell tumbling. We deduce that individual bacteria entering a flow system can rapidly migrate upstream (>20 μm/s) much faster than a gradually advancing biofilm. Given a bacterial population with a distribution of sizes and swim speeds, local shear rate near the surface determines the dominant hydrodynamic mode for motility, i.e., circular or random trajectories for low shear rates, positive rheotaxis for moderate flow, and sideways swimming at higher shear rates. Faster swimmers can move upstream more rapidly and at higher shear rates, as expected. Interestingly, we also find on average that both swim speed and upstream motility are independent of cell aspect ratio.

Original languageEnglish
Pages (from-to)1514-1523
Number of pages10
JournalBiophysical Journal
Issue number7
Publication statusPublished - 4 Apr 2012
Externally publishedYes


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