{{Short description|Phylum of bacteria}} {{About|the bacterial phylum|spiral-shaped bacteria in general|spiral bacteria}} {{Use dmy dates|date=July 2020}} {{automatic taxobox | name = Spirochaetes | image2 = Treponema pallidum.jpg | image2_caption = ''Treponema pallidum'', a spirochaete which causes syphilis | parent_authority = Garrity and Holt 2021<ref>{{cite journal | vauthors = Oren A, Garrity GM | title = Valid publication of the names of forty-two phyla of prokaryotes | journal = Int J Syst Evol Microbiol | year = 2021 | volume = 71 | issue = 10 | page = 5056 | doi = 10.1099/ijsem.0.005056 | pmid = 34694987 | s2cid = 239887308 | doi-access = free }}</ref> | taxon = Spirochaetia | authority = Paster 2020<ref name = "Paster_2010">{{cite book | vauthors = Paster BJ | chapter = Class I. Spirochaetia class. nov. | veditors = Krieg NR, Staley JT, Brown DR, Hedlund BP, Paster BJ | title = Bergey's Manual of Systematic Bacteriology | volume = 4—The Bacteroidetes, Spirochaetes, Tenericutes (Mollicutes), Acidobacteria, Fibrobacteres, Fusobacteria, Dictyoglomi, Gemmatimonadetes, Lentisphaerae, Verrucomicrobia, Chlamydiae, and Planctomycetes | edition = 2nd | publisher = Springer | location = New York, NY | year = 2010 | doi = 10.1007/978-0-387-68572-4| isbn = 978-0-387-95042-6 }}</ref>{{rp|471–563}}<ref>{{cite journal | vauthors = Oren A, Garrity GM | title = Validation list no. 195. List of new names and new combinations previously effectively, but not validly, published | journal = Int J Syst Evol Microbiol | year = 2020 | volume = 70 | issue = 9 | pages = 4844–4847 | doi = 10.1099/ijsem.0.004366| pmid = 32993851 | s2cid = 222147003 | doi-access = free }}</ref> | subdivision_ranks = Orders | subdivision = * Brachyspirales * Brevinematales * Leptospirales * Spirochaetales * "Treponematales" | synonyms = Spirochaetota: * "Protozoobacteriales" <small>Prévot 1958</small> * "Spirochaetae" <small>Cavalier-Smith 2002</small> * "Spirochaetaeota" <small>Oren et al. 2015</small> * "Spirochaetes" <small>Garrity and Holt 2001</small> * "Spirochaetota" <small>Whitman et al. 2018</small> Spirochaetia: * Spirochaetes <small>Cavalier-Smith 2002</small> * "Spirochaetia" <small>Cavalier-Smith 2020</small> * "Leptospiria" <small>Cavalier-Smith 2020</small> }} thumb|250px|Cross section of a spirochaete cell thumb|Endoflagella Components. Legend: Fig. 1: A cross-section of a typical spirochete cell showing endoflagella located in the periplasm between the inner cytoplasmic membrane and the outer membrane. Periplasm, consisting of a gel-like matrix, provides a semi-stable medium to secure endoflagella during rotation. The axial filament, indicated in red, is composed of bundles of endoflagella.<br /> Fig. 2: A side-view of a spirochete cell which shows two axial filaments in opposing motion. One axial filament rotates in a clockwise orientation; an adjacent axial filament rotates in a counter-clockwise orientation. Rotation of the endoflagella creates torsion and drives the corkscrew rotation of the cell.<br /> Fig. 3: An expanded view of the cellular membranes that surround endoflagellum. Both the inner and outer membrane contain a phospholipid bi-layer, with non-polar fatty acid chains in-ward of polar phosphorus heads. Peptidoglycan, the cell wall, provides structure in bacterial microorganisms. Axial filaments are superior to the peptidoglycan.
A '''spirochaete''' ({{IPAc-en|ˈ|s|p|aɪ|r|oʊ|ˌ|k|iː|t}})<ref>{{cite web |url=https://www.lexico.com/definition/spirochaete |archive-url=https://web.archive.org/web/20210127083406/https://www.lexico.com/definition/spirochaete |archive-date=27 January 2021 |title=SPIROCHAETE | Meaning & Definition for UK English | Lexico.com|website=Lexico Dictionaries | English}}</ref> or '''spirochete''' is a member of the phylum '''Spirochaetota''' (also called '''Spirochaetes'''<ref name="Dorlands">{{cite book |title=Dorland's Illustrated Medical Dictionary |publisher=Elsevier |url=https://dorlands.com/}}</ref> {{IPAc-en|ˌ|s|p|aɪ|r|oʊ|ˈ|k|iː|t|iː|z}}), which contains distinctive diderm (double-membrane) Gram-negative bacteria, most of which have long, helically coiled (corkscrew-shaped or spiraled, hence the name) cells.<ref name=Sherris>{{cite book | veditors = Ryan KJ, Ray CG | title = Sherris Medical Microbiology | edition = 4th | publisher = McGraw Hill | year = 2004 | isbn = 978-0-8385-8529-0 }}</ref> Spirochaetes are chemoheterotrophic in nature, with lengths between 3 and 500 μm and diameters around 0.09 to at least 3 μm.<ref>{{cite journal | vauthors = Margulis L, Ashen JB, Solé M, Guerrero R | title = Composite, large spirochetes from microbial mats: spirochete structure review | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 90 | issue = 15 | pages = 6966–6970 | date = August 1993 | pmid = 8346204 | pmc = 47056 | doi = 10.1073/pnas.90.15.6966 | bibcode = 1993PNAS...90.6966M | doi-access = free | author-link = Lynn Margulis }}</ref>
Spirochaetes are distinguished from other bacterial phyla by the location of their flagella, called '''endoflagella''', or '''periplasmic flagella''', which are sometimes called ''axial filaments''.<ref name="Nakamura">{{cite journal |vauthors=Nakamura S |title=Spirochete Flagella and Motility |journal=Biomolecules |volume=10 |issue=4 |date=April 2020 |page=550 |pmid=32260454 |pmc=7225975 |doi=10.3390/biom10040550 |url= |doi-access=free }}</ref><ref name="McGraw">{{cite web | vauthors = Carroll KC, Hobden JA, Miller S |title=Spirochetes and Other Spiral Microorganisms |url=https://accessmedicine.mhmedical.com/content.aspx?bookid=1551§ionid=94107920 |website=Jawetz, Melnick, & Adelberg's Medical Microbiology |publisher=McGraw-Hill Education |access-date=9 May 2021 |date=2019}}</ref> Endoflagella are anchored at each end (pole) of the bacterium within the periplasmic space (between the inner and outer membranes) where they project backwards to extend the length of the cell.<ref name="Brock">{{cite book | vauthors = Madigan MT |title=Brock biology of microorganisms |date=2019 |publisher=Pearson |location=NY, NY |isbn=978-1-292-23510-3 |page=519 |edition=Fifteenth, Global}}</ref> These cause a twisting motion which allows the spirochaete to move. When reproducing, a spirochaete will undergo asexual transverse binary fission. Most spirochaetes are free-living and anaerobic, but there are numerous exceptions. Spirochaete bacteria are diverse in their pathogenic capacity and the ecological niches that they inhabit, as well as molecular characteristics including guanine-cytosine content and genome size.<ref name="Paster_2011">{{cite book | vauthors = Paster BJ | date = 2011 | chapter = Phylum XV. Spirochaetes Garrity and Holt. | title = Bergey's Manual of Systematic Bacteriology | page = 471 | veditors = Brenner DJ, Krieg NR, Garrity GM, Staley JT | publisher = Springer | location = New York }}</ref><ref name="Paster_2011b">{{cite book | vauthors = Paster BJ | date = 2011 | chapter = Family I. Sprochaetes Swellengrebel 1907, 581AL. | title = Bergey's Manual of Systematic Bacteriology | pages = 473–531 | veditors = Brenner DJ, Krieg NR, Garrity GM, Staley JT | publisher = Springer | location = New York}}</ref>
==Pathogenicity== Many organisms within the Spirochaetota phylum cause prevalent diseases. Pathogenic members of this phylum include the following: * ''Leptospira'' species, which causes leptospirosis<ref name=McBride_2005>{{cite journal |vauthors=McBride A, Athanazio D, Reis M, Ko A |title=Leptospirosis |journal=Current Opinion in Infectious Diseases |volume=18 |issue=5 |pages=376–86 |year=2005 |pmid=16148523 |doi=10.1097/01.qco.0000178824.05715.2c|s2cid=220576544 }}</ref> * ''Borrelia burgdorferi'', ''B. mayonii'', ''B. bissettiae'', ''B. garinii'', ''B. afzelii'', ''B. spielmanii'', ''B. lusitaniae'', which cause Lyme disease.<ref>{{cite journal | vauthors = Wolcott KA, Margos G, Fingerle V, Becker NS | title = Host association of Borrelia burgdorferi sensu lato: A review | journal = Ticks and Tick-Borne Diseases | volume = 12 | issue = 5 | article-number = 101766 | date = September 2021 | pmid = 34161868 | doi = 10.1016/j.ttbdis.2021.101766 }}</ref> * ''Borrelia recurrentis'', which causes relapsing fever<ref name=Schwan_1996>{{cite journal | vauthors = Schwan TG | title = Ticks and Borrelia: model systems for investigating pathogen-arthropod interactions | journal = Infectious Agents and Disease | volume = 5 | issue = 3 | pages = 167–181 | date = June 1996 | pmid = 8805079 }}</ref> * ''Treponema pallidum'' subspecies which cause treponematoses such as syphilis and yaws. * ''Brachyspira pilosicoli'' and ''Brachyspira aalborgi'', which cause intestinal spirochaetosis<ref name=pmid14718105>{{cite journal |vauthors=Amat Villegas I, Borobio Aguilar E, Beloqui Perez R, de Llano Varela P, Oquiñena Legaz S, Martínez-Peñuela Virseda JM |title=[Colonic spirochetes: an infrequent cause of adult diarrhea] |language=es|journal=Gastroenterol Hepatol |volume=27 |issue=1 |pages=21–3 |date=January 2004 |pmid=14718105 |doi= 10.1016/s0210-5705(03)70440-3}}</ref> <!--Spirochaetes may also cause dementia and may be involved in the pathogenesis of Alzheimer's disease.<ref>{{cite journal | vauthors = Miklossy J | title = Alzheimer's disease - a neurospirochetosis. Analysis of the evidence following Koch's and Hill's criteria | journal = Journal of Neuroinflammation | volume = 8 | page = 90 | date = August 2011 | pmid = 21816039 | pmc = 3171359 | doi = 10.1186/1742-2094-8-90 }}</ref>--> Salvarsan, the first partially organic synthetic antimicrobial drug in medical history, was effective against spirochaetes and primarily used to cure syphilis. Additionally, oral spirochaetes are known to play a significant role in the pathogenesis of human periodontal disease.<ref>{{cite journal | vauthors = Yousefi L, Leylabadlo HE, Pourlak T, Eslami H, Taghizadeh S, Ganbarov K, Yousefi M, Tanomand A, Yousefi B, Kafil HS | display-authors = 6 | title = Oral spirochetes: Pathogenic mechanisms in periodontal disease | journal = Microbial Pathogenesis | volume = 144 | article-number = 104193 | date = July 2020 | pmid = 32304795 | doi = 10.1016/j.micpath.2020.104193 | s2cid = 215818931 }}</ref>
==Taxonomy and molecular signatures== The class currently consists of 14 validly named genera across four orders and five families.<ref name=NCBI/><ref name="pmid23908650">{{cite journal |vauthors=Gupta RS, Mahmood S, Adeolu M |title= A phylogenomic and molecular signature based approach for characterization of the phylum Spirochaetes and its major clades: proposal for a taxonomic revision of the phylum |journal= Front Microbiol |volume=4 |issue=217 |page= 217 |year=2013 |pmid=23908650 |doi=10.3389/fmicb.2013.00217 |pmc=3726837|doi-access= free }}</ref><ref name="Oren & Garrity ">{{cite journal |vauthors=Oren A, Garrity GM |title= List of new names and new combinations previously effectively, but not validly, published |journal=Int. J. Syst. Evol. Microbiol.|volume=64 |issue= 3 |pages=693–696|date=2014 |doi=10.1099/ijs.0.062521-0 |url=http://www.microbiologyresearch.org/docserver/fulltext/ijsem/64/3/693_ijs062521.pdf?expires=1477417542&id=id&accname=guest&checksum=2C44BCAA8040751280AC24CAF29DC185 }}</ref> The orders ''Brachyspirales'', ''Brevinematales'' and ''Leptospirales'' each contain a single family, ''Brachyspiraceae'', ''Brevinemataceae'' and ''Leptospiraceae'', respectively. The ''Spirochaetales'' order harbours two families, ''Spirochaetaceae'' and ''Borreliaceae''. Molecular markers in the form of conserved signature indels (CSIs) and CSPs have been found specific for each of the orders, with the exception of ''Brevinimetales'', that provide a reliable means to demarcate these clades from one another within the diverse phylum.<ref name="pmid23908650"/> Additional CSIs have been found exclusively shared by each family within the ''Spirochaetales''. These molecular markers are in agreement with the observed phylogenetic tree branching of two monophyletic clades within the ''Spirochaetales'' order.<ref name="pmid23908650"/> CSIs have also been found that further differentiate taxonomic groups within the ''Borreliaceae'' family that further delineate evolutionary relationships that are in accordance with physical characteristics such as pathogenicity (viz. ''Borrelia'' emend. ''Borreliella'' gen. nov.).<ref name=pmid24744012>{{cite journal |vauthors=Adeolu M, Gupta RS |title=A phylogenomic and molecular marker based proposal for the division of the genus Borrelia into two genera: the emended genus Borrelia containing only the members of the relapsing fever Borrelia, and the genus Borreliella gen. nov. containing the members of the Lyme disease Borrelia (Borrelia burgdorferi sensu lato complex)|journal=Antonie van Leeuwenhoek |volume=105 |issue=6 |pages=1049–1072|date=2014|pmid=24744012|doi=10.1007/s10482-014-0164-x }}</ref> However, this study has been criticized, and other studies using different approaches do not support the proposed split.<ref name="Winslow2019">{{cite journal |vauthors=Winslow C, Coburn J |title=Recent discoveries and advancements in research on the Lyme disease spirochete Borrelia burgdorferi |journal=F1000Research |volume=8 |page= 763|date=2019 |pmid=31214329 |pmc=6545822 |doi=10.12688/f1000research.18379.1 |doi-access=free }}</ref> The new naming system for the Lyme and relapsing fever ''Borrelia'' has not been adopted by the scientific literature.<ref name="Winslow2019"/>
A CSI has also been found exclusively shared by all Spirochaetota species.<ref name="pmid23908650"/> This CSI is a three-amino-acid insert in the flagellar basal body rod protein FlgC which is an important part of the unique endoflagellar structure shared by Spirochaetota species.<ref name=Macnab03>{{cite journal |vauthors=Macnab RM |title=How bacteria assemble flagella|journal=Annu Rev Microbiol |volume=57 |pages=77–100|date=2003 |pmid=12730325 |doi=10.1146/annurev.micro.57.030502.090832}}</ref> Given that the CSI is exclusively shared by members within this phylum, it has been postulated that it may be related to the characteristic flagellar properties observed among Spirochaetota species.<ref name="pmid23908650"/><ref name=Macnab03/>
Historically, all families belonging to the Spirochaetota phylum were assigned to a single order, the ''Spirochaetales''.<ref name="Paster_2011"/><ref name="Paster_2011b"/> However, the current taxonomic view is more connotative of accurate evolutionary relationships. The distribution of a CSI is indicative of shared ancestry within the clade for which it is specific. It thus functions as a synapomorphic characteristic, so that the distributions of different CSIs provide the means to identify different orders and families within the phylum and so justify the phylogenetic divisions.<ref name="pmid23908650"/>
==Phylogeny== {{see also|Bacterial taxonomy}} {| class="wikitable" |- ! colspan=1 | 16S rRNA based LTP_10_2024<ref>{{cite web|title=The LTP |url=https://imedea.uib-csic.es/mmg/ltp/#LTP| access-date=10 December 2024}}</ref><ref>{{cite web|title=LTP_all tree in newick format| url=https://imedea.uib-csic.es/mmg/ltp/wp-content/uploads/ltp/LTP_all_10_2024.ntree |access-date=10 December 2024}}</ref><ref>{{cite web|title=LTP_10_2024 Release Notes| url=https://imedea.uib-csic.es/mmg/ltp/wp-content/uploads/ltp/LTP_10_2024_release_notes.pdf |access-date=10 December 2024}}</ref> ! colspan=1 | 120 marker proteins based GTDB 10-RS226<ref name="about">{{cite web |title=GTDB release 10-RS226 |url=https://gtdb.ecogenomic.org/about#4%7C |website=Genome Taxonomy Database|access-date=1 May 2025}}</ref><ref name="tree">{{cite web |title=bac120_r226.sp_label |url=https://data.gtdb.ecogenomic.org/releases/release226/226.0/auxillary_files/bac120_r226.sp_labels.tree |website=Genome Taxonomy Database|access-date=1 May 2025}}</ref><ref name="taxon_history">{{cite web |title=Taxon History |url=https://gtdb.ecogenomic.org/taxon_history/ |website=Genome Taxonomy Database|access-date=1 May 2025}}</ref> |- | style="vertical-align:top| {{Clade | style=font-size:90%;line-height:80% |label1=Brevinematia |1={{clade |label1=Brevinematales |1={{clade |label1=Brevinemataceae |1=''Brevinema'' |label2=Thermospiraceae |2=''Thermospira'' }} }} }} {{Clade | style=font-size:90%;line-height:80% |label1=Spirochaetia |1={{clade |1={{clade |label1=Leptospirales |1={{clade |label1=Leptospiraceae |1={{clade |1=''Turneriella'' |2={{clade |1=''Leptonema'' |2=''Leptospira'' }} }} }} }} |2={{clade |1={{clade |label1="Exilispirales" |1={{clade |label1="Exilispiraceae" |1=''Exilispira'' }} |label2=Brachyspirales |2={{clade |label1=Brachyspiraceae |1=''Brachyspira'' }} }} |2={{clade |label1=Spirochaetales |1={{clade |1={{clade |1={{clade |label1=Sphaerochaetaceae |1={{clade |1=''Pleomorphochaeta'' |2={{clade |1=''Bullifex'' |2=''Sphaerochaeta'' }} }} }} |2={{clade |1={{clade |label1=Rectinemataceae |1=''Rectinema'' }} |2={{clade |label1=Breznakiellaceae |1={{clade |1={{clade |1=''Gracilinema'' |2=''Zuelzera'' }} |2={{clade |1=''Breznakiella'' |2={{clade |1=''Treponema primitia'' |2={{clade |1=''Helmutkoenigia'' |2=''Leadbettera'' }} }} }} }} |label2=Treponemataceae |2={{clade |1={{clade |1={{clade |1=''Brucepastera'' |2=''Teretinema'' }} |2=''Treponema'' }} |2=''Treponema'' species-group 2 }} }} }} }} |2={{clade |1={{clade |label1=Marispirochaetaceae |1=''Marispirochaeta'' |label2=Sediminispirochaetaceae |2=''Sediminispirochaeta'' }} |2={{clade |1=''Spirochaeta thermophila'' |2={{clade |1={{clade |1={{clade |label1=Salinispiraceae |1={{clade |1=''Spirochaeta lutea'' |2=''Salinispira'' }} |label2=Spirochaetaceae |2=''Spirochaeta'' }} |2={{clade |label1=Alkalispirochaetaceae |1={{clade |1=''Spirochaeta halophila'' |2=''Alkalispirochaeta'' }} }} }} |2={{clade |1=''Spirochaeta aurantia'' |2={{clade |1={{clade |label1=Spirochaetaceae 2 |1={{clade |1=''Spirochaeta cellobiosiphila'' |2={{clade |1=''Oceanispirochaeta'' |2={{clade |1=''Thiospirochaeta'' |2=''Spirochaeta'' species-group 2 }} }} }} }} |2={{clade |label1="Entomospiraceae" |1=''Entomospira'' |label2=Borreliaceae |2={{clade |1=''Borrelia'' |2=''Borreliella'' }} }} }} }} }} }} }} }} }} }} }} }} | {{clade|style=font-size:90%;line-height:80% |1={{Clade |label1="Leptospirae" |1={{clade |label1=Leptospiria |1={{clade |label1=Turneriellales |1={{clade |label1=Turneriellaceae |1=''Turneriella'' }} |label2=Leptospirales |2={{clade |label1=Leptonemataceae |1=''Leptonema'' |label2=Leptospiraceae |2=''Leptospira'' }} }} }} |label2="Euspirochaetae" |2={{clade |1={{clade |label1=Brevinematia |1={{clade |label1=Brevinematales |1={{clade |label1=Brevinemataceae |1=''Brevinema'' |label2=Thermospiraceae |2=''Thermospira'' }} }} }} |2={{clade |1={{clade |label1=Brachyspiria |1={{clade |label1=Brachyspirales |1={{clade |label1=Brachyspiraceae |1=''Brachyspira'' }} }} }} |2={{clade |label1="Exilispiria" |1={{clade |label1="Exilispirales" |1={{clade |label1="Exilispiraceae" |1=''Exilispira'' }} }} |label2=Spirochaetia |2={{clade |1={{clade |label1=Borreliales |1={{clade |label1=Borreliaceae |1={{clade |1=''Borrelia'' |2=''Borreliella'' }} }} }} |2={{clade |1={{clade |label1=SP-2023 |1={{clade |label1=SP-2023 |1="''Ca.'' Haliotispira" }} }} |2={{clade |1={{clade |label1="Entomospirales" |1={{clade |label1="Entomospiraceae" |1=''Entomospira'' }} }} |2={{clade |1={{clade |label1=Spirochaetales_E |1={{clade |1={{clade |label1="Thiospirochaetaceae" |1=''Thiospirochaeta'' }} |2={{clade |label1=DSM-2461 |1=''Spirochaeta''_F |label2=Spirochaetaceae_B |2=''Oceanispirochaeta'' }} }} }} |2={{clade |1={{clade |label1=DSM-17781 |1={{clade |label1=DSM-17781 |1=''Spirochaeta cellobiosiphila'' }} }} |2={{clade |1={{clade |label1=Winmispirales |1={{clade |label1=Winmispiraceae |1=''Winmispira'' }} |label2="Salinispirales" |2={{clade |1={{clade |label1=DSM-8902 |1=''Spirochaeta africana'' |label2="Salinispiraceae" |2={{clade |1=''Spirochaeta lutea'' |2=''Salinispira'' }} }} |2={{clade |label1="Alkalispirochaetaceae" |1=''Alkalispirochaeta'' }} }} }} |2={{clade |1={{clade |1={{clade |label1="Sediminispirochaetales" |1={{clade |label1=Sediminispirochaetaceae |1=''Sediminispirochaeta'' }} }} |2={{clade |label1=UBA9216 |1={{clade |label1=UBA9216 |1="''Ca.'' Thalassospirochaeta" }} |label2="Marispirochaetales" |2={{clade |label1=Marispirochaetaceae |1=''Marispirochaeta'' }} }} }} |2={{clade |label1=Sphaerochaetales |1={{clade |label1=Sphaerochaetaceae |1={{clade |1={{clade |1=''Parasphaerochaeta'' |2=''Sphaerochaeta'' }} |2={{clade |1=''Bullifex'' |2="''Ca.'' Ornithospirochaeta" }} }} }} |label2=Treponematales |2={{clade |1={{clade |label1=Rectinemataceae |1=''Rectinema'' }} |2={{clade |label1=Breznakiellaceae |1={{clade |1=''Gracilinema'' |2={{clade |1=''Treponema primitia'' |2={{clade |1=''Breznakiella'' |2=''Leadbettera'' }} }} }} |label2=Treponemataceae |2={{clade |1={{clade |1="''Ca.'' Gallitreponema" |2=''Treponema''_C, D, E, F }} |2={{clade |1={{clade |1="''Ca.'' Avitreponema" |2={{clade |1=''Brucepastera'' |2=''Teretinema'' }} }} |2=''Treponema'' }} }} }} }} }} }} }} }} }} }} }} }} }} }} }} }} }} |}
==Taxonomy== The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN)<ref name=LPSN>{{lpsn3|phylum/spirochaetota|Spirochaetota}}</ref> and National Center for Biotechnology Information (NCBI).<ref name=NCBI>{{cite web |author=Schoch CL |display-authors=et al. |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&mode=tree&id=203691&lvl=3 |title=Spirochaetota |accessdate=2025-06-05 |publisher=National Center for Biotechnology Information (NCBI) taxonomy database}}</ref> * Phylum '''Spirochaetota''' <small>Garrity and Holt 2021</small> ** Genus ?"''Spirosymplokos''" <small>Guerrero et al. 1993</small> ** Class '''Leptospiria''' <small>Chuvochina et al. 2024</small> *** Order '''Turneriellales''' <small>Chuvochina et al. 2024</small> **** Family Turneriellaceae <small>Chuvochina et al. 2024</small> ***** Genus ''Turneriella'' <small>Levett et al. 2005</small> *** Order '''Leptospirales''' <small>Gupta et al. 2014</small> **** Family Leptonemataceae <small>Chuvochina et al. 2024</small> ***** Genus ''Leptonema'' <small>Hovind-Hougen 1983</small> **** Family Leptospiraceae <small>Hovind-Hougen 1979</small> ***** Genus ''Leptospira'' <small>Noguchi 1917</small> ** Class '''Brevinematia''' <small>Chuvochina et al. 2024</small> *** Order '''Brevinematales''' <small>Gupta et al. 2014</small> **** Family "Longinemataceae" <small>Karnachuk et al. 2021</small> ***** Genus ?"''Longinema''" <small>corrig. Karnachuk et al. 2021</small> **** Family Brevinemataceae <small>Paster 2012</small> ***** Genus ''Brevinema'' <small>Defosse et al. 1995</small> **** Family Thermospiraceae <small>Ben Ali Gam et al. 2023</small> ***** Genus ''Thermospira'' <small>Ben Ali Gam et al. 2023</small> ** Class '''Brachyspiria''' <small>Chuvochina et al. 2024</small> *** Order '''Brachyspirales''' <small>corrig. Gupta et al. 2014</small> **** Family Brachyspiraceae <small>Paster 2012</small> ***** Genus ?"''Ca.'' Maribrachyspira" <small>Matsuyama et al. 2017</small> ***** Genus ''Brachyspira'' <small>Hovind-Hougen et al. 1982 non Foliella non Pfeiffer 1855</small> ** Class '''Spirochaetia''' <small>Paster 2020</small> *** Order '''Spirochaetales''' <small>Buchanan 1917</small> **** Family "Pillotinaceae" <small>Margulis & Hinkle 1992</small> ***** Genus ?''Pillotina'' <small>Hollande and Gharagozlou 1967 ex Bermudes et al. 1988</small> **** Family Spirochaetaceae <small>Swellengrebel 1907</small> ["Thiospirochaetaceae" <small>Pallen, Rodriguez-R & Alikhan 2022</small>] ***** Genus ?"''Ca.'' Allospironema" <small>Paster & Dewhirst 2000</small> ***** Genus ?"''Canaleparolina''" <small>Wier, Ashen & Margulis 2000</small> ***** Genus ?''Clevelandina'' <small>Bermudes et al. 1988</small> ***** Genus ?''Diplocalyx'' <small>Gharagozlou 1968 ex Bermudes et al. 1988 non Richard 1850 non Presl 1845</small> ***** Genus ?''Hollandina'' <small>To et al. 1978 ex Bermudes et al. 1988 non Haynes 1956</small> ***** Genus ?"''Mobilifilum''" <small>Margulis et al. 1990</small> ***** Genus ?''Rarispira'' <small>Podosokorskaya et al. 2025</small> ***** Genus ?"''Spirophis''" <small>(Warming 1875) Lauterborn 1916 </small> ***** Genus ?''Spirochaeta'' <small>Ehrenberg 1835 em. Pikuta et al. 2009 non Turczaninow 1851</small> ***** Genus "''Ca.'' Haliotispira" <small>Sharma et al. 2024</small> *** Order "'''Exilispirales'''" <small>Pallen, Rodriguez-R & Alikhan 2022</small> **** Family "Exilispiraceae" <small>Pallen, Rodriguez-R & Alikhan 2022</small> ***** Genus ''Exilispira'' <small>Imachi et al. 2008</small> *** Order '''Borreliales''' <small>Chuvochina et al. 2024</small> **** Family Borreliaceae <small>Gupta et al. 2014</small> ***** Genus ''Borrelia'' <small>Swellengrebel 1907</small> (relapsing fever Borrelia, reptile-associated Borrelia and Echidna-associated Borrelia) ***** Genus ''Borreliella'' <small>Adeolu & Gupta 2015</small> (Lyme disease Borrelia) ***** Genus ?''Cristispira'' <small>Gross 1910</small> *** Order "'''Entomospirales'''" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [WRBN01] **** Family "Entomospiraceae" <small>Pallen, Rodriguez-R & Alikhan 2022</small> ***** Genus ''Entomospira'' <small>Grana-Miraglia et al. 2024 non Enderlein 1917</small> *** Order "'''Salinispirales'''" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DSM-27196] **** Family "Thiospirochaetaceae" <small>Pallen, Rodriguez-R & Alikhan 2022</small> [DSM-19205] ***** Genus ''Oceanispirochaeta'' <small>Subhash & Lee 2017b</small> ***** Genus "''Ca.'' Thalassospirochaeta" <small>Pragya et al. 2024</small> ***** Genus ''Thiospirochaeta'' <small>Dubinina et al. 2020</small> **** Family Alkalispirochaetceae <small>Chuvochina et al. 2024</small> ***** Genus ''Alkalispirochaeta'' <small>Sravanthi et al. 2016</small> **** Family Salinispiraceae <small>Chuvochina et al. 2024</small> ***** Genus ''Salinispira'' <small>Ben Hania et al. 2015</small> *** Order '''Winmispirales''' <small>Podosokorskaya et al. 2025</small> [DSM-6578] **** Family Winmispiraceae <small>Podosokorskaya et al. 2025</small> ***** Genus ''Winmispira'' <small>Podosokorskaya et al. 2025</small> *** Order "'''Sediminispirochaetales'''" <small>Pallen, Rodriguez-R & Alikhan 2022</small> **** Family Sediminispirochaetaceae <small>Chuvochina et al. 2024</small> ***** Genus ''Sediminispirochaeta'' <small>Shivani et al. 2016</small> *** Order "'''Marispirochaetales'''" <small>Pallen, Rodriguez-R & Alikhan 2022</small> **** Family Marispirochaetaceae <small>Chuvochina et al. 2024</small> ***** Genus ''Marispirochaeta'' <small>Shivani et al. 2017</small> *** Order '''Sphaerochaetales''' <small>Chuvochina et al. 2024</small> **** Family Sphaerochaetaceae <small>Hördt et al. 2020</small> ***** Genus ''Bullifex'' <small>Wylensek et al. 2021</small> [incl. "''Ca.'' Aphodenecus" <small>Gilroy et al. 2021</small>] ***** Genus "''Ca.'' Ornithospirochaeta" <small>Gilroy et al. 2021</small> ***** Genus ''Parasphaerochaeta'' <small>Bidzhieva et al. 2020</small> ***** Genus ?"''Ca.'' Physcosoma" <small>Gilroy et al. 2022</small> ***** Genus ?''Pleomorphochaeta'' <small>Arroua et al. 2016</small> ***** Genus ''Sphaerochaeta'' <small>Ritalahti et al. 2012</small> *** Order '''Treponematales''' <small>Chuvochina et al. 2024</small> **** Family Rectinemataceae <small>Brune et al. 2022</small> ***** Genus ''Rectinema'' <small>Koelschbach et al. 2017</small> **** Family Breznakiellaceae <small>Brune et al. 2022</small> ***** Genus ''Breznakiella'' <small>Song et al. 2022</small> ***** Genus ''Gracilinema'' <small>Brune et al. 2022</small> ***** Genus ?''Helmutkoenigia'' <small>Brune et al. 2022</small> ***** Genus ''Leadbettera'' <small>Brune et al. 2022</small> ***** Genus ?"''Propulsinema''" <small>Fu et al. 2025</small> ***** Genus ?''Zuelzera'' <small>Brune et al. 2022</small> **** Family Treponemataceae <small>Robinson 1948</small> ***** Genus "''Ca.'' Avitreponema" <small>Gilroy et al. 2021</small> ***** Genus ''Brucepastera'' <small>Song et al. 2023</small> ***** Genus "''Ca.'' Gallitreponema" <small>Gilroy et al. 2021</small> ***** Genus ''Teretinema'' <small>Song et al. 2023</small> ***** Genus ''Treponema'' <small>Schaudinn 1905 em. Abt et al. 2013</small>
== See also == {{col div|colwidth=30em}} * List of bacteria genera * List of bacterial orders * Bacteriology * Borrelia * ''Brevinema andersonii'' * Flagellum * Lyme disease microbiology * Pinta (disease) * Prokaryote * Syphilis * ''Treponema pallidum'' * Yaws {{colend}}
== References == <!-- --------------------------------------------------------------- See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for a discussion of different citation methods and how to generate footnotes using the <ref> & </ref> tags and the {{Reflist}} template -------------------------------------------------------------------- --> {{Reflist}}
== External links == * [http://www.ucmp.berkeley.edu/bacteria/spirochetes.html Introduction to the Spirochetes] University of California Museum of Paleontology (UCMP)
{{Portal bar|Biology}} {{Bacteria classification}} {{Life on Earth}} {{Taxonbar|from=Q12673555}} Category:Spirochaetes Category:Bacteria phyla