Spirochetal motility and chemotaxis in the natural enzootic cycle and development of Lyme disease

Two-thirds of all bacterial genomes sequenced to-date possess an organelle for locomotion, referred to as flagella, periplasmic flagella or type IV pili. These genomes may also contain a chemotaxis-signaling system which governs flagellar rotation, thus leading a coordinated function for motility. Motility and chemotaxis are often crucial for infection or disease process caused by pathogenic bacteria. Although motility-associated genes are well-characterized in some organisms, the highly orchestrated synthesis, regulation, and assembly of periplasmic flagella in spirochetes are just being delineated. Recent advances were fostered by development of unique genetic manipulations in spirochetes coupled with cutting-edge imaging techniques. These contemporary advances in understanding the role of spirochetal motility and chemotaxis in host persistence and disease development are highlighted in this review.