Cross section of a spirochaete cell
Spirochaetes (also spelled spirochetes) belong to a phylum of distinctive diderm (double-membrane) bacteria, most of which have long, helically coiled (spiral-shaped) cells. Spirochaetes 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 bacterial inner membrane and outer membrane in periplasmic space. These cause a twisting motion which allows the spirochaete to move about. When reproducing, a spirochaete will undergo asexual transverse binary fission.
Most spirochaetes are free-living and anaerobic, but there are numerous exceptions.
The spirochaetes are divided into three families (Brachyspiraceae, Leptospiraceae, and Spirochaetaceae), all placed within a single order (Spirochaetales). Disease-causing members of this phylum include the following:
Cavalier-Smith has postulated that the Spirochaetes belong in a larger clade called Gracilicutes.
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN)  and National Center for Biotechnology Information (NCBI) and the phylogeny is based on 16S rRNA-based LTP release 111 by 'The All-Species Living Tree' Project 
♦ Type strain lost or not available
♪ Prokaryotes where no pure (axenic) cultures are isolated or available, i. e. not cultivated or can not be sustained in culture for more than a few serial passages
♠ Strains found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LSPN)
Salvarsan, the first partially organic antimicrobial drug in medical history, was effective against spirochaetes only and was primarily used to cure syphilis.
See also 
- ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.
- ^ McBride A, Athanazio D, Reis M, Ko A (2005). "Leptospirosis". Curr Opin Infect Dis 18 (5): 376–86. doi:10.1097/01.qco.0000178824.05715.2c. PMID 16148523.
- ^ Schwan T (1996). "Ticks and Borrelia: model systems for investigating pathogen-arthropod interactions". Infect Agents Dis 5 (3): 167–81. PMID 8805079.
- ^ Amat Villegas I, Borobio Aguilar E, Beloqui Perez R, de Llano Varela P, Oquiñena Legaz S, Martínez-Peñuela Virseda JM (January 2004). "[Colonic spirochetes: an infrequent cause of adult diarrhea]". Gastroenterol Hepatol (in Spanish; Castilian) 27 (1): 21–3. PMID 14718105.
- ^ Cavalier-Smith, T., T (2006). "Rooting the tree of life by transition analyses". Biology Direct 1 (19): 19. doi:10.1186/1745-6150-1-19. PMC 1586193. PMID 16834776.
- ^ J.P. Euzéby. "Spirochaetes". List of Prokaryotic names with Standing in Nomenclature (LPSN) . Retrieved 2013-03-20.
- ^ Sayers et al. "Spirochaetes". National Center for Biotechnology Information (NCBI) taxonomy database . Retrieved 2013-03-20.
- ^ 'The All-Species Living Tree' Project."16S rRNA-based LTP release 111 (full tree)". Silva Comprehensive Ribosomal RNA Database . Retrieved 2013-03-20.
External links