Yersinia enterocolitica
Yersinia enterocolitica is a species of gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

A coccobacillus is a type of rod-shaped bacteria. The word coccobacillus reflects an intermediate shape between coccus and bacillus . Coccobacilli rods are so short and wide that they resemble cocci. Haemophilus influenzae and Chlamydia trachomatis are coccobacilli...

 bacterium, belonging to the family Enterobacteriaceae
The Enterobacteriaceae is a large family of bacteria that includes many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella. This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the...

. Yersinia enterocolitica infection causes the disease yersiniosis, which is a zoonotic
A zoonosis or zoonoseis any infectious disease that can be transmitted from non-human animals to humans or from humans to non-human animals . In a study of 1415 pathogens known to affect humans, 61% were 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 carrier
Asymptomatic carrier
An asymptomatic carrier is a person or other organism that has contracted an infectious disease, but who displays no symptoms. Although unaffected by the disease themselves, carriers can transmit it to others...


Signs and symptoms

Acute Y. enterocolitica infections usually lead to mild self-limiting entero
In medicine, enteritis, from Greek words enteron and suffix -itis , refers to inflammation of the small intestine. It is most commonly caused by the ingestion of substances contaminated with pathogenic microorganisms. Symptoms include abdominal pain, cramping, diarrhea, dehydration and fever...

In medicine, colitis refers to an inflammation of the colon and is often used to describe an inflammation of the large intestine .Colitides may be acute and self-limited or chronic, i.e...

 or terminal ileitis
Ileitis is an inflammation of the ileum, a portion of the small intestine. Crohn's ileitis is a type of Crohn's disease affecting the ileum. Ileitis is caused by the bacteria Lawsonia intracellularis....

 in humans. Symptoms may include watery or bloody diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

 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
Lymphadenopathy is a term meaning "disease of the lymph nodes." It is, however, almost synonymously used with "swollen/enlarged lymph nodes". It could be due to infection, auto-immune disease, or malignancy....

. This condition can be confused with appendicitis
Appendicitis is a condition characterized by inflammation of the appendix. It is classified as a medical emergency and many cases require removal of the inflamed appendix, either by laparotomy or laparoscopy. Untreated, mortality is high, mainly because of the risk of rupture leading to...

 and is therefore called pseudoappendicitis. In immunosuppressed individuals, yersiniae can disseminate from the gut to liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

 and spleen
The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...

 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
Yersiniosis is an infectious disease caused by a bacterium of the genus Yersinia. In the United States, most yersiniosis infections among humans are caused by Y. enterocolitica. Yersiniosis is mentioned as a specific zoonotic disease to prevent outbreaks in European Council Directive...

 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 infections are sometimes followed by chronic inflammatory diseases such as arthritis
Arthritis is a form of joint disorder that involves inflammation of one or more joints....


Y. enterocolitica seems to be associated with autoimmune Graves-Basedow
Graves-Basedow disease
Graves' disease is an autoimmune disease where the thyroid is overactive, producing an excessive amount of thyroid hormones...

Thyroiditis is the inflammation of the thyroid gland. The thyroid gland is located on the front of the neck below the laryngeal prominence, and makes hormones that control metabolism.-Classification:...

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
Causality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....

 of auto-immune thyroid disease, but rather is only an associated
Association (statistics)
In statistics, an association is any relationship between two measured quantities that renders them statistically dependent. The term "association" refers broadly to any such relationship, whereas the narrower term "correlation" refers to a linear relationship between two quantities.There are many...

 condition; with both having a shared inherited susceptibility.
More recently the role for Y. enterocolitica has been disputed.

External links

  • Yersinia enterocolitica genomes and related information at PATRIC
    PATRIC, the Pathosystems Resource Integration Center, is one of the four Bioinformatics Resource Centers funded by the National Institutes of Allergy and Infectious Diseases, NIAID a component of the National Institutes of Health , which is an agency of the United States Department of Health and...

    , a Bioinformatics Resource Center funded by NIAID
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