The Chlamydiaceae are a family of
gram-negative bacteria 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
The bacterial 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. Chlam ...
. Chlamydiaceae species express the family-specific
lipopolysaccharide epitope αKdo-(2→8)-αKdo-(2→4)-αKdo (previously called the genus-specific epitope). Chlamydiaceae
ribosomal 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'' 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
ribosomal operons.
''Chlamydia trachomatis'' is the cause of an infection commonly
transmitted sexually (often referred as just "Chlamydia") and also is the cause of
trachoma, 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 (LPSN)
and
National Center for Biotechnology Information (NCBI)
* "''Ca.''
Amphibiichlamydia"
Martel et al. 2012
* ''
Chlamydia''
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
See also
*
List of bacterial orders
*
List of bacteria genera
References
{{Authority control
Chlamydiota
Bacteria families