The Chlamydiaceae are a family of

gram-negative bacteria Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...

that belongs to the phylum

Chlamydiota The Chlamydiota (synonym Chlamydiae) are a bacterial phylum and class whose members are remarkably diverse, including pathogens of humans and animals, symbionts of ubiquitous protozoa, and marine sediment forms not yet well understood. All of th ...

, order Chlamydiales. Chlamydiaceae species express the family-specific

lipopolysaccharide Lipopolysaccharides (LPS) are large molecules consisting of a lipid and a polysaccharide that are bacterial toxins. They are composed of an O-antigen, an outer core, and an inner core all joined by a covalent bond, and are found in the outer m ...

epitope An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. The epitope is the specific piece of the antigen to which an antibody binds. The p ...

αKdo-(2→8)-αKdo-(2→4)-αKdo (previously called the genus-specific epitope). Chlamydiaceae

ribosomal Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to fo ...

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

genes all have at least 90% DNA sequence identity. Chlamydiaceae species have varying inclusion morphology, varying extrachromosomal

plasmid A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; how ...

content, and varying sulfadiazine resistance. The family Chlamydiaceae currently includes one genus and one candidate genus: ''

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 wee ...

'' and ''candidatus Clavochlamydia''.

''Chlamydia''

Three species belong to ''Chlamydia'': ''C. trachomatis'', ''C. muridarum'', and ''C. suis''. ''C. trachomatis'' has been found only in humans, ''C. muridarum'' in hamsters and mice (family

Muridae The Muridae, or murids, are the largest family of rodents and of mammals, containing approximately 1,383 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia. The name Muridae come ...

), and ''C. suis'' in swine. ''Chlamydia'' species produce a small amount of detectable

glycogen Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body. Glycogen functions as one o ...

and have two

operon In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splic ...

s. ''Chlamydia trachomatis'' is the cause of an infection commonly transmitted sexually (often referred as just "Chlamydia") and also is the cause of

trachoma Trachoma is an infectious disease caused by bacterium ''Chlamydia trachomatis''. The infection causes a roughening of the inner surface of the eyelids. This roughening can lead to pain in the eyes, breakdown of the outer surface or cornea of ...

, an infectious eye disease, spread by eye, nose, and throat secretions.

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 naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclature ...

(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. The ...

(NCBI) * "''Ca.'' Amphibiichlamydia" Martel et al. 2012 * ''

'' 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

References

{{Authority control Chlamydiota Bacteria families

''Chlamydia''

Phylogeny

Taxonomy

See also

References