Characterization of hydrodynamic surface interactions of Escherichia coli cell bodies in shear flow.

We experimentally demonstrate that nonflagellated Escherichia coli strains follow modified Jeffery orbits in shear flow near a surface. We fully characterize their Jeffery orbits as a function of their aspect ratios and distance from that surface. Thanks to the linearity of Navier-Stokes equations under low-Reynolds-number conditions, the hydrodynamic body-wall interactions described here can be superimposed with flagellar motility and Brownian motion to construct models that explain the full picture of bacterial motility near a surface under shear flow.