Yersinia enterocolitica

There are 3 pathogenic species in the genus Yersinia, but only Y. enterocolitica and Y. pseudotuberculosis cause gastroenteritis. Food borne outbreaks caused by Y. pseudotuberculosis have been reported in Japan. Y. pestis , the causative agent of "the plague," is genetically very similar to Y. pseudotuberculosis but infects humans by routes other than food.

Yersiniosis is frequently characterized by such symptoms as gastroenteritis with diarrhea and/or vomiting; but, fever and abdominal pain are hallmark symptoms. Yersinia infections mimic appendicitis and mesenteric lymphadenitis, but may also cause infections of other sites such as wounds, joints and the urinary tract.

Illness onset starts 24 and 48 hours after ingestion, which (with food or drink as vehicle) is the usual route of infection.

 

Diagnosis of yersiniosis begins with isolation it from the indivual's feces, blood, or vomit, and sometimes at the time of appendectomy. Confirmation occurs with the isolation, as well as biochemical and serological identification, of Y. enterocolitica from both the human host and the food. Diarrhea is reported in 80% of cases; abdominal pain and fever are the most reliable symptoms.

Because of the difficulties in isolating yersiniae from feces, several countries rely on serology. Acute and convalescent patient sera are titered against the suspect serotype of Yersinia spp . Yersiniosis has been misdiagnosed as appendicitis

Y. enterocolitica can be found in meats (pork, beef, lamb, etc.), oysters, fish, and raw milk. The exact cause of the food contamination is unknown. Poor sanitation and improper sterilization techniques by food handlers, including improper storage, contribute to contamination. It is rare unless a breakdown occurs in food processing techniques.

CDC estimates that about 17,000 cases occur annually in the USA but it is far more common in Northern Europe, Scandinavia, and Japan.

The major "complication" is the performance of unnecessary appendectomies, since one of the main symptoms of infections is abdominal pain of the lower right quadrant.

Both Y. enterocolitica and Y. pseudotuberculosis are associated with reactive arthritis, which may occur alone even in the absence of obvious symptoms.

Another rare complication is bacteremia (entrance of organisms into the blood stream.

Reference : Yersinia enterocolitica incidents MMWR 39(45):1990 Nov 16