The Clostridiaceae are a family of 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 among ...

l class

Clostridia The Clostridia are a highly polyphyletic class of Bacillota, including ''Clostridium'' and other similar genera. They are distinguished from the Bacilli by lacking aerobic respiration. They are obligate anaerobes and oxygen is toxic to them. S ...

, and contain the genus '' Clostridium''. The family Clostridiaceae (scientific name) defined by the taxonomic outline of '' Bergey's Manual of Systematic Bacteriology '' contains as its core the genus '' Clostridium'' (''sensu stricto''), as well as ''

Acetivibrio ''Acetivibrio'' is a genus of Clostridia The Clostridia are a highly polyphyletic class of Bacillota, including ''Clostridium'' and other similar genera. They are distinguished from the Bacilli by lacking aerobic respiration. They are oblig ...

'', ''

Acidaminobacter ''Acidaminobacter'' is a genus in the phylum Bacillota (Bacteria). Etymology The name ''Acidaminobacter'' derives from New Latin ''acidum aminum'', amino acid, a rod'' bacter'', nominally meaning "a rod", but in effect meaning a bacterium, a s ...

'', ''

Alkaliphilus ''Alkaliphilus'' is a bacterium from the family of Clostridiaceae The Clostridiaceae are a family of the bacterial class Clostridia, and contain the genus '' Clostridium''. The family Clostridiaceae (scientific name) defined by the taxonomi ...

'', '' Anaerobacter'', ''

Caloramator ''Caloramator'', is a genus of bacteriae belonging to the Bacillota The Bacillota (synonym Firmicutes) are a phylum of bacteria, most of which have gram-positive cell wall structure. The renaming of phyla such as Firmicutes in 2021 remains con ...

'', ''

Caloranaerobacter ''Caloranaerobacter'' is a Gram-negative, thermophilic, anaerobic and chemoorganotrophic bacterial genus from the family of Clostridiaceae The Clostridiaceae are a family of the bacterial class Clostridia, and contain the genus '' Clostridiu ...

'', '' Coprobacillus'', '' Dorea'', ''

Natronincola ''Natronincola'' is a genus of bacteria from the family of Clostridiaceae The Clostridiaceae are a family of the bacterial class Clostridia, and contain the genus '' Clostridium''. The family Clostridiaceae (scientific name) defined by the ...

'', ''

Oxobacter ''Oxobacter'' is a genus of Gram-positive obligately anaerobic rod-shaped acetogenic bacteria. The sole species in the genus is ''Oxobacter pfennigii'', formerly known as ''Clostridium pfennigii''. This endospore-forming microorganism cataboliz ...

'', ''

Sarcina The ''sarcina'' was the marching pack carried by Roman legionaries, the heavy infantry of the Roman legions. Most of a legionary's equipment other than his arms and armour would, in early times, have been consigned to a baggage train and b ...

'', '' Sporobacter'', ''

Thermobrachium ''Thermobrachium'' is an obligate anaerobic, moderately alkaliphilic, thermophilic and proteolytic genus of bacteria from the family of Clostridiaceae The Clostridiaceae are a family of the bacterial class Clostridia, and contain the genus ' ...

'', ''

Thermohalobacter ''Thermohalobacter'' is a Gram-negative, thermophilic, strictly halophilic, non- spore-forming anaerobic, rod-shaped and motile genus of bacteria from the family of Clostridiaceae with one known species ('' Thermohalobacter berrensis''). ''Therm ...

'', and ''

Tindallia ''Tindallia'' is a genus of bacteria from the family of Clostridiaceae The Clostridiaceae are a family of the bacterial class Clostridia, and contain the genus '' Clostridium''. The family Clostridiaceae (scientific name) defined by the tax ...

''. The previous inclusion of these additional genera (as seen on the right) in a family Clostridiaceae is based for the most part because the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of these genera are in many cases phylogenetically related to misclassified species of the genus ''Clostridium''. However, with the exception of ''Anaerobacter'', ''Caloramator'', ''Oxobacter'', ''Sarcina'', and ''Thermobrachium'', these genera fall outside the radiation of what can be considered the true family Clostridiaceae and are now regarded as belonging to other families within the low G + C, Gram-positive phylum. This misclassification is the result of well-known problems of the current taxonomic structure of the traditional genus ''Clostridium''. The phylogenetic analysis of Collins (1994) was the first large-scale comparison of 16S rRNA gene sequences of species of the genus ''Clostridium'' and related taxa. The fact that the species of the genus ''Clostridium'' did not form a monophyletic group has been shown in a number of studies in which small groups of ''Clostridium'' species had been compared as far back as 1981. The comparative study of Collins (1994) and subsequent studies can be used to conclude that more than half of the species currently assigned to this genus are in fact not closely related to the type species, '' C. butyricum'', and from a phylogenetic standpoint should not be included in a newly defined genus ''Clostridium''. This extensive genetic diversity of the genus ''Clostridium'' had been shown using 23S rRNA:DNA hybridization studies back in 1975 by Johnson and Francis, but the 16S rRNA gene sequence approach revealed the actual phylogenetic relationships between the species of this genus and other genera. The genus ''Clostridium'' currently comprises 152 validly described species in nomenclature.www.bacterio.net
/ref> However, on the basis of 16S rRNA gene sequence analyses, only 73 of these fall within the radiation of the type species of the genus ''Clostridium''.

Subdivisions

The

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

family Clostridiaceae comprises the following:

References

{{Taxonbar, from=Q592153

Subdivisions

See also

References