The Yersiniaceae are a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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 includes some familiar pathogens. For example, the type genus ''

Yersinia ''Yersinia'' is a genus of bacteria in the family Yersiniaceae. ''Yersinia'' species are Gram-negative, coccobacilli bacteria, a few micrometers long and fractions of a micrometer in diameter, and are facultative anaerobes. Some members of ''Yer ...

'' includes ''

Yersinia pestis ''Yersinia pestis'' (''Y. pestis''; formerly '' Pasteurella pestis'') is a gram-negative, non-motile, coccobacillus bacterium without spores that is related to both ''Yersinia pseudotuberculosis'' and ''Yersinia enterocolitica''. It is a facult ...

'', the causative agent of

plague Plague or The Plague may refer to: Agriculture, fauna, and medicine *Plague (disease), a disease caused by ''Yersinia pestis'' * An epidemic of infectious disease (medical or agricultural) * A pandemic caused by such a disease * A swarm of pes ...

. This family is a member of the order

Enterobacterales Enterobacterales is an order of Gram-negative, non-spore forming, facultatively anaerobic, rod-shaped bacteria with the class Gammaproteobacteria. The type genus of this order is ''Enterobacter.'' The name Enterobacterales is derived from the ...

in the class

Gammaproteobacteria Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota (synonym Proteobacteria). It contains about 250 genera, which makes it the most genera-rich taxon of the Prokaryotes. Several medically, ecologically, and scientifically imp ...

of the phylum

Pseudomonadota Pseudomonadota (synonym Proteobacteria) is a major phylum of Gram-negative bacteria. The renaming of phyla in 2021 remains controversial among microbiologists, many of whom continue to use the earlier names of long standing in the literature. The ...

. The name Yersiniaceae is derived from the Latin term ''Yersinia'', referring the

type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal f ...

of the family and the suffix "-aceae", an ending used to denote a family. Together, Yersiniaceae refers to a family whose nomenclatural type is the genus ''Yersinia''.

Biochemical characteristics and molecular signatures

These bacteria are

motile Motility is the ability of an organism to move independently, using metabolic energy. Definitions Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms th ...

, catalase-positive, and do not produce

hydrogen disulfide Hydrogen disulfide is the inorganic compound with the formula H2S2. This hydrogen chalcogenide is a pale yellow volatile liquid with a camphor-like odor. It decomposes readily to hydrogen sulfide (H2S) and elemental sulfur.R. Steudel "Inorgani ...

. Analyses of genome sequences from Yersiniaceae species identified three

conserved signature indels Conserved signature inserts and deletions (CSIs) in protein sequences provide an important category of molecular markers for understanding phylogenetic relationships. CSIs, brought about by rare genetic changes, provide useful phylogenetic markers ...

(CSIs) that are uniquely present in this family in the proteins TetR family

transcriptional regulator In molecular biology and genetics, transcriptional regulation is the means by which a cell regulates the conversion of DNA to RNA ( transcription), thereby orchestrating gene activity. A single gene can be regulated in a range of ways, from a ...

and a hypothetical protein. These CSIs provide a reliable molecular method for distinguishing members of this family from other families within the order Enterobacterales and all other bacteria.

Historical systematics and current taxonomy

Yersiniaceae, as of 2021, contains eight validly published genera. Members of this family were originally members of the family

Enterobacteriaceae Enterobacteriaceae is a large family (biology), family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject ...

, a large phylogenetically unrelated group of species with distinct biochemical characteristics and different ecological niches. The original assignment of species into the family Enterobacteriaceae was largely based on 16S rRNA genome sequence analyses, which is known to have low discriminatory power and the results of which changes depends on the algorithm and organism information used. Despite this, the analyses still exhibited polyphyletic branching, indicating the presence of distinct subgroups within the family. In 2016, Adeolu et al. proposed the division of Enterobacteriaceae into 7 novel families based on comparative genomic analyses and the branching pattern of various phylogenetic trees constructed from conserved genome sequences, 16S rRNA sequences and multilocus sequence analyses. Molecular markers, specifically

, specific to this family were also identified as evidence supporting the division independent of phylogenetic trees.

References

Gram-negative bacteria Enterobacterales Bacteria families {{gammaproteobacteria-stub