Phylum Spirochaetes

 Phylum Spirochaetes

The Spirochaetes are distinguished from all other bacteria by their slender helical mor-phology and corkscrew-like movement. This is made possible by endoflagella (axial filaments), so-called because they are enclosed in the space between the cell and a flexi-ble sheath that surrounds it.

Spirochaetes comprise both aerobic and anaerobic bacteria that inhabit a wide range of habitats, including water and soil as well as the gut and oral cavities of both vertebrate and invertebrate animals. Some species are important pathogens of humans, including Treponema pallidum (syphilis) and Leptospira interrogans (leptospirosis).

Representative genera: Treponema, Leptospira

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