Final answer:
Spirochetes utilize an axial filament for locomotion, which enables their unique corkscrew-like movement, aiding in the infection process for pathogenic species.
Step-by-step explanation:
The method of locomotion unique to spirochetes is achieved through the use of an axial filament. This structure, which resembles a flagellum but is distinct in its location and movement, wraps around the cell body and runs in the periplasmic space between the bacterium's inner and outer membranes. When the axial filament rotates, it imparts a twisting motion to these spiral-shaped bacteria, allowing them to move in a corkscrew-like fashion through viscous environments, such as connective tissue, which may be part of the pathogenesis of diseases they are known to cause, such as syphilis, Lyme disease, and leptospirosis.