|Yersinia enterocolitica colonies growing on XLD agar plates.|
(Schleifstein & Coleman 1939)
|Classification and external resources|
Yersinia enterocolitica is a species of gram-negative coccobacillus-shaped bacterium, belonging to the family Enterobacteriaceae. Yersinia enterocolitica infection causes the disease yersiniosis, which is a zoonotic disease occurring in humans as well as a wide array of animals such as cattle, deer, pigs, and birds. Many of these animals recover from the disease and become asymptomatic carriers. It infects the host by sticking to the cells of the host using Trimeric Autotransporter Adhesins (TAA).
Signs and symptoms 
Acute Y. enterocolitica infections usually lead to mild self-limiting entero-colitis or terminal ileitis in humans. Symptoms may include watery or bloody diarrhea and fever. After oral uptake yersiniae replicate in the terminal ileum and invade Peyer's patches. From here yersiniae can disseminate further to mesenteric lymph nodes causing lymphadenopathy. This condition can be confused with appendicitis and is therefore called pseudoappendicitis. In immunosuppressed individuals, yersiniae can disseminate from the gut to liver and spleen and form abscesses. Because Yersinia is a siderophilic (iron-loving) bacteria, people with hereditary hemochromatosis (a disease resulting in high body iron levels) are more susceptible to infection with Yersinia (and other siderophilic bacteria). In fact, the most common contaminant of stored blood is Y. enterocolitica. See yersiniosis for further details. Yersiniae are usually transmitted to humans by insufficiently cooked pork or contaminated water.
Yersiniosis is usually self-limiting and does not require treatment. Severe infections (septicemia, focal infection, immunosuppression) can be treated with doxycycline in combination with an aminoglycoside. Other antibiotics that are active against Y. enterocolitica include trimethoprim-sulfamethoxasole, fluoroquinolones, ceftriaxone, and chloramphenicol. Y. enterocolitica is usually resistant to penicillin G, ampicillin, and cephalotin due to beta-lactamase production.
Y. enterocolitica seems to be associated with autoimmune Graves-Basedow thyroiditis. Whilst indirect evidence exists, direct causative evidence is limited, and Y. enterocolitica is probably not a major cause of this disease, but may contribute to the development of thyroid autoimmunity arising for other reasons in genetically susceptible individuals. It has also been suggested that Y. enterocolitica infection is not the cause of auto-immune thyroid disease, but rather is only an associated condition; with both having a shared inherited susceptibility. More recently the role for Y. enterocolitica has been disputed.
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|Wikispecies has information related to: Yersinia enterocolitica|
- Yersinia enterocolitica genomes and related information at PATRIC, a Bioinformatics Resource Center funded by NIAID