The

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

l order Chlamydiales includes only obligately intracellular bacteria that have a chlamydia-like developmental cycle of replication and at least 80% 16S rRNA or 23S rRNA gene sequence identity with other members of Chlamydiales. Chlamydiales live in animals, insects, and protozoa. Currently, the order Chlamydiales includes the families

Chlamydiaceae The Chlamydiaceae are a family of gram-negative bacteria that belongs to the phylum Chlamydiota, order Chlamydiales. Chlamydiaceae species express the family-specific lipopolysaccharide epitope αKdo-(2→8)-αKdo-(2→4)-αKdo (previously call ...

, Simkaniaceae, and

Waddliaceae ''Waddlia'' is a genus of bacteria in its own family, Waddliaceae. Species in this genus have a ''Chlamydia''-like cycle of replication and their ribosomal RNA genes are 80–90% identical to ribosomal genes in the Chlamydiaceae. The type spe ...

, which have Gram-negative extracellular infectious bodies (EBs), and Parachlamydiaceae, which has variable Gram staining of EBs. The family

Rhabdochlamydiaceae ''Candidatus'' Rhabdochlamydia is a genus of intracellular bacteria and the sole genus in the family ''Candidatus'' Rhabdochlamydiaceae. As a ''Candidatus'' taxon, no-one has yet managed to culture them ''in vitro'' for deposition in a culture co ...

has been proposed.

Phylogeny

Taxonomy

The currently accepted taxonomy is based on the

List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the nomenclature, naming and Taxonomy (biology), taxonomy of prokaryotes, following the taxonomy requirements and rulings of the In ...

(LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. Th ...

(NCBI) * Family " Actinochlamydiaceae" Steigen et al. 2013 ** ?"''Ca.'' Actinochlamydia" Steigen et al. 2013 * Family " Clavichlamydiaceae" Horn 2011 ** "''Ca.'' Clavichlamydia" corrig. Karlsen et al. 2008 * Family " Criblamydiaceae" Thomas, Casson & Greub 2006 ** '' Criblamydia'' Thomas, Casson & Greub 2006 ** '' Estrella'' Thomas et al. 2006 * Family

Rake 1957 ** "''Ca.'' Amphibiichlamydia" Martel et al. 2012 ** ''

Chlamydia Chlamydia, or more specifically a chlamydia infection, is a sexually transmitted infection caused by the bacterium '' Chlamydia trachomatis''. Most people who are infected have no symptoms. When symptoms do appear they may occur only several we ...

'' Jones et al. 1945 ** "'' Chlamydiifrater''" Vorimore et al. 2021 ** ''

Chlamydophila ''Chlamydophila'' is a controversial bacterial genus belonging to the family Chlamydiaceae. Taxonomy All Chlamydiota are anaerobic bacteria with a biphasic developmental lifecycle that depends on obligately intracellular growth in eukaryotic h ...

'' Everett, Bush & Andersen 1999 ** ?"''Ca.'' Medusoplasma" Viver et al. 2017 * Family Parachlamydiaceae Everett, Bush & Andersen 1999 ** ?"''Ca.'' Mesochlamydia" Corsaro et al. 2012 ** ?"''Ca.'' Metachlamydia" Corsaro et al. 2010 ** '' Neochlamydia'' Horn et al. 2001 ** ''

Parachlamydia ''Parachlamydia'', is a genus of bacteriae belonging to the Chlamydiota. Species include '' P. acanthamoeba''. See also * List of bacterial orders * List of bacteria genera This article lists the genera of the bacteria. The currently accepted t ...

'' Everett, Bush & Andersen 1999 ** "''Ca.'' Protochlamydia" Collingro et al. 2005 ** "''Ca.'' Rubidus" Pagnier et al. 2015 * Family

Corsaro et al. 2009 ** ?"''Ca.'' Renichlamydia" Corsaro & Work 2012 ** "''Ca.''

Rhabdochlamydia ''Candidatus'' Rhabdochlamydia is a genus of intracellular bacteria and the sole genus in the family ''Candidatus'' Rhabdochlamydiaceae. As a ''Candidatus'' taxon, no-one has yet managed to culture them ''in vitro'' for deposition in a culture co ...

" Kostanjsek et al. 2004 * Family Simkaniaceae Everett, Bush & Andersen 1999 ** ?"''Ca.'' Fritschea" Everett et al. 2005 ** "''Ca.'' Neptunochlamydia" Pizzetti et al. 2016 ** '' Simkania'' Everett, Bush & Andersen 1999 ** ?"''Ca.'' Syngnamydia" Fehr et al. 2013 * Family

Rurangirwa et al. 1999 ** Genus '' Waddlia'' Rurangirwa et al. 1999

References

Chlamydiota Bacteria orders {{Bacteria-stub