  The near-surface swimming patterns of bacteria are strongly determined by the
hydrodynamic interactions between bacteria and the surface, which trap bacteria
in smooth circular trajectories that lead to inefficient surface exploration.
Here, we show by combining experiments and a data-driven mathematical model
that surface exploration of enterohemorrhagic Escherichia coli (EHEC) -- a
pathogenic strain of E. coli causing serious illnesses such as bloody diarrhea
-- results from a complex interplay between motility and transient surface
adhesion events. These events allow EHEC to break the smooth circular
trajectories and regulate their transport properties by the use stop-adhesion
events that lead to a characteristic intermittent motion on surfaces. We find
that the experimentally measured frequency of stop-adhesion events in EHEC is
located at the value predicted by the developed mathematical model that
maximizes bacterial surface diffusivity. We indicate that these results and the
developed model apply to other bacterial strains on different surfaces, which
suggests that swimming bacteria use transient adhesion to regulate surface
motion.
