''Yersinia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

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

in the family

Yersiniaceae The Yersiniaceae are a family of Gram-negative bacteria that includes some familiar pathogens. For example, the type genus ''Yersinia'' includes ''Yersinia pestis'', the causative agent of plague. This family is a member of the order Enterobacter ...

. ''Yersinia'' species are

Gram-negative 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 wa ...

, coccobacilli

, a few micrometers long and fractions of a micrometer in diameter, and are

facultative anaerobe A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent. Some examples of facultatively anaerobic bacteria are '' Staphylococc ...

s. Some members of ''Yersinia'' are pathogenic in humans; in particular, '' Y. pestis'' is the causative agent of the

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 pe ...

Rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

s are the natural reservoirs of ''Yersinia''; less frequently, other

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...

serve as the host. Infection may occur either through blood (in the case of ''Y. pestis'') or in an

alimentary The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

fashion, occasionally via consumption of food products (especially vegetables, milk-derived products, and meat) contaminated with infected

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...

or feces. Speculations exist as to whether or not certain ''Yersinia'' can also be spread by protozoan, protozoonotic mechanisms, since ''Yersinia'' species are known to be facultative intracellular parasites; studies and discussions of the possibility of amoeba-vectored (through the cyst form of the protozoan) ''Yersinia'' propagation and proliferation are now in progress.

Microbial physiology

An interesting feature peculiar to some of the ''Yersinia'' bacteria is the ability to not only survive, but also to actively proliferate at temperatures as low as 1–4 °C (e.g., on cut salads and other food products in a refrigerator). ''Yersinia'' bacteria are relatively quickly inactivated by oxidizing agents such as hydrogen peroxide and potassium permanganate solutions.

Genetics

Database

The creation of YersiniaBase, a data and tools collection for the reporting and comparison of ''Yersinia'' species genome sequence data, was reported in January 2015. The provisional representation of species addressed by the resource has been indicated in the TaxBox on this page by a superscript 'yb' beside the species name. Development of YersiniaBase was funded by the University of Malaya and the Ministry of Education (Malaysia), Ministry of Education, Malaysia.

Pathogenesis

''Y. pestis'' is the causative agent of

. The disease caused by ''Yersinia enterocolitica, Y. enterocolitica'' is called yersiniosis. ''Yersinia'' may be associated with Crohn's disease, an inflammatory autoimmune condition of the gut. Iranian sufferers of Crohn's disease were more likely to have had earlier exposure to refrigerators at home, consistent with its unusual ability to thrive at low temperatures. ''Yersinia'' is implicated as one of the causes of reactive arthritis worldwide. Also, the genus is associated with pseudoappendicitis, which is an incorrect diagnosis of appendicitis due to a similar presentation.

History

''Y. pestis'', the first known species, was identified in 1894 by Alexandre Emile John Yersin, A.E.J. Yersin, a Swiss bacteriologist, and Kitasato Shibasaburō, a Japanese bacteriologist. It was formerly described as ''Pasteurella pestis'' (known Common name, trivially as the plague-bacillus) by Lehmann and Neumann in 1896. In 1944, van Loghem reclassified the species ''P. pestis'' and ''P. rondentium'' into a new genus, ''Yersinia''. Following the introduction of the bacteriological code, it was accepted as valid in 1980.

References

External links

''Yersinia'' Enterocolitis Mimicking Crohn's Disease in a ToddlerSweden: Pork warnings over new stomach illness

''Yersinia''
genomes and related information a
PATRIC
a Bioinformatics Resource Center funded b
NIAID
* {{Taxonbar, from=Q132231 Yersinia, Bacteria genera