  Bacterial migration through confined spaces is critical for several phenomena
like: biofilm formation, bacterial transport in soils, and bacterial therapy
against cancer . In the present work, \textit{E. coli} (strain K12-MG1655 WT)
motility was characterized by recording and analyzing individual bacterium
trajectories in a simulated quasi-2-dimensional porous medium. The porous
medium was simulated by enclosing, between slide and cover slip, a
bacterial-culture sample mixed with uniform 2.98 $\mu m$ spherical latex
particles. The porosity of the medium was controlled by changing the latex
particle concentration. By statistically analyzing trajectory parameters like:
instantaneous velocity and turn angle, as well as mean squared displacement, we
were able to quantify the effects that different latex particle concentrations
have upon bacterial motility. To better understand our results, bacterial
trajectories were simulated by means of a phenomenological random-walk model
(developed ad hoc), and the simulated results were compared with the
experimental ones.
