Yersinia

Yersinia is a genus of bacteria in the family Yersiniaceae.<ref>Template:Cite journal</ref> Yersinia species are Gram-negative, coccobacilli bacteria, and are facultative anaerobes.<ref name=Sherris>Template:Cite book</ref> Three members of Yersinia are pathogenic in humans: Y. pestis causes the plague and Y. enterocolitica and Y. pseudotuberculosis cause gastrointestinal syndromes. Rodents are the natural reservoirs of Yersinia; less frequently, other mammals serve as the host. Infection may occur either through blood (in the case of Y. pestis) or in an alimentary fashion, occasionally via consumption of food products (especially vegetables, milk-derived products, and meat) contaminated with infected urine or feces.

Speculations exist as to whether or not certain Yersinia can also be spread by protozoonotic mechanisms, since Yersinia species are known to be facultative intracellular parasites; currently, there are studies and discussions of the possibility of amoeba-vectored (through the cyst form of the protozoan) Yersinia propagation and proliferation.<ref>Template:Cite journal</ref>

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).<ref>Template:Cite journal</ref> Yersinia bacteria are relatively quickly inactivated by oxidizing agents such as hydrogen peroxide and potassium permanganate solutions.

Pathology

Y. pestis is the causative agent of plague. The disease caused by Y. enterocolitica is called yersiniosis.

Yersinia may be associated with Crohn's disease, an inflammatory autoimmune condition of the gut. Iranian people with Crohn's disease were more likely to have had earlier exposure to refrigerators at home,<ref name="ibs-fridge">Template:Cite journal</ref> consistent with its unusual ability to thrive at low temperatures.

Yersinia is implicated as one of the causes of reactive arthritis worldwide.<ref>Template:Cite journal</ref>

Also, the genus is associated with pseudoappendicitis, which is an incorrect diagnosis of appendicitis due to a similar presentation.<ref>Template:Cite web</ref>

Pathogenesis

Effector proteins

All pathogenic Yersinia have effector proteins that are injected into host cells using a type-three secretion system (T3SS), including 6 Yop proteins. Pathogenic Y. enterocolitica has a different effector protein family composed of 8 Ysp proteins. These effector proteins disrupt the cytoskeleton, phagocytosis, and various immune responses.<ref>Template:Cite journal</ref>

History

Template:For Template:See also Y. pestis, the first known species, was identified in 1894<ref>Template:Cite web</ref> by A.E.J. Yersin, a Swiss bacteriologist, and Kitasato Shibasaburō, a Japanese bacteriologist.<ref name=VL44>Template:Cite journal</ref> It was formerly described as Pasteurella pestis (known trivially as the plague-bacillus) by Lehmann and Neumann in 1896.<ref name=VL44/><ref name=lpsn>Template:Lpsn</ref> In 1944, van Loghem reclassified the species P. pestis and P. rondentium into a new genus, Yersinia.<ref name=VL44/><ref name=lpsn/> Following the introduction of the bacteriological code, it was accepted as valid in 1980.<ref name=lpsn/>

External links

• Yersinia Enterocolitis Mimicking Crohn's Disease in a Toddler
• Sweden: Pork warnings over new stomach illness
• Yersinia genomes and related information at PATRIC, a Bioinformatics Resource Center funded by NIAID