LAUSR

Significance Acanthamoeba are considered among the most predominant and efficient microscale predators in environments such as soil and natural water systems. While it is known that Acanthamoeba castellanii employ a “backpacking” strategy to trap and aggregate bacterial prey prior to phagocytosis, a mechanistic understanding of this fascinating predation strategy has been lacking. By integrating microfluidics, high-resolution microscopy, and state-of-the-art image-analysis methods, we discovered that capture dynamics of Listeria monocytogenes by A. castellanii are mediated purely by random encounters, further enhanced by bacterial motility. Furthermore, tracking of captured L. monocytogenes on the outer surface of A. castellanii indicates a crucial role of the amoeba locomotion in the assembly of trapped cells into backpacks.