My topic is to explore the upstream swimming dynamics of Escherichia coli in meter-long microfluidic channels and tubing to determine how bacteria contaminate distant sites from their initial colony, a critical yet poorly understood factor in microbial infections. Despite decades of research on E. coli upstream motility, the mechanisms enabling long-distance transport remain unclear. By analyzing swimming behavior and contamination patterns in ultra-long channels, this study aims to uncover the biophysical principles governing bacterial migration over extended distances, providing new insights into infection spread and informing strategies for preventing microbial contamination in biological and medical settings.