What is the Difference Between Spirilla and Spirochetes?

Spirilla and Spirochetes are both types of spiral-shaped bacteria, but they have distinct differences in their cell structure, flexibility, and motility mechanisms. The main differences between Spirilla and Spirochetes include:

1. Cell Structure: Spirilla have a rigid cell wall, while Spirochetes have a flexible cell wall.
2. Size: Spirochetes are very thin and elongated, whereas Spirilla are not as long and thin.
3. Motility: Spirilla use bipolar flagella for locomotion, while Spirochetes rely on axial filaments (internal periplasmic flagella) for movement.
4. Pathogenicity: Spirochetes are generally considered more pathogenic than Spirilla, causing deadlier diseases.

Examples of Spirilla include members of the genus Spirillum, Campylobacter species, and Helicobacter species. Spirochetes examples include Leptospira species, Borrelia species (such as B. burgdorferi, causing Lyme disease), and Treponema species (such as T. pallidum, causing syphilis).

Comparative Table: Spirilla vs Spirochetes

Spirilla and Spirochetes are both spiral-shaped bacteria, but they have some differences in their structure and motility mechanisms. Here is a table comparing the two:

Spirilla possess polar flagella for locomotion, while Spirochetes have axial filaments arising from the periplasmic space for their movement. Spirilla bacteria have relatively short and rigid cells, while Spirochetes have longer and more flexible cells. Spirilla are found in chains of cells, whereas Spirochetes exist as individual cells. Additionally, Spirochetes do not have a cell wall, but Spirilla do. Some species of Spirilla, such as S. minor, can cause diseases like rat bite fever in humans, while Spirochetes are known to cause more severe diseases.