Yersinia enterocolitica

Yersinia enterocolitica is a species of gram-negative coccobacillus-shaped bacterium, belonging to the family Enterobacteriaceae. Primarily a zoonotic disease (cattle, deer, pigs, and birds), animals that recover frequently become asymptomatic carriers of the disease.

Pathogenesis

Acute infections

Acute Y. enterocolitica infections produce severe diarrhea in humans, along with Peyer's patch necrosis, chronic lymphadenopathy, and hepatic or splenic abscesses. Additional symptoms may include entero-colitis, fever, mesenteric adenitis, erythema nodosum and acute terminal ileitis, which may be confused with appendicitis or Crohn's disease. Because Yersinia is a siderophilic (iron-loving) bacteria, those with hereditary hemochromatosis (a disease resulting in high body iron levels) are more susceptible to infection with Yersinia (and other siderophilic bacteria). See yersiniosis for further details.

Treatment

Treatment of Y. enterocolitica infections often requires aggressive antibiotic therapy, typically involving ciprofloxacin, chloramphenicol, ampicillin, and polymyxin. However, some gastoenterologists, especially in Scandinavia, would say that antibiotic treatment should be initiated only when the patient has significant and persisting symptoms of gastroenteritis.

Long-term effects

Y. enterocolitica infections are sometimes followed by chronic inflammatory diseases such as arthritis.

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.