Final answer:
Some intracellular pathogens can use unipolar structures to mediate host cell actin polymerization, which gives the microbe motility within the host cell.
Step-by-step explanation:
Some intracellular pathogens can use unipolar structures to mediate host cell actin polymerization, which gives the microbe motility within the host cell.
In order to avoid being killed by the phagolysosome, the mechanism that relies most upon motility is escape of the phagosome.
Pathogens such as Listeria monocytogenes and Shigella produce proteins that lyse the phagosome before it fuses with the lysosome, allowing the bacteria to escape into the phagocyte's cytoplasm and avoid digestion.