Spirochaetes (also spelled Spirochetes) belong to a phylum of distinctive Gram-negative bacteria, which have long, helically coiled (spiral-shaped) cells. Spirochetes are chemoheterotrophic in nature, with lengths between 5 and 250 µm and diameters around 0.1-0.6 µm. Spirochaetes are distinguished from other bacterial phyla by the location of their flagella, sometimes called axial filaments, which run lengthwise between the cell membrane and outer membrane. These cause a twisting mot… (More on Spirochaete)