Yersinia enterocolitica
Yersinia enterocolitica is a gram -ve bacterium that belongs to a family of rod-shaped bacteria. Other species of bacteria in this family include Yersinia pseudotuberculosis, which causes an illness similar to Yersinia enterocolitica and Yersinia pestis, which causes plague.
Yersinia enterocolitica can cause illness in humans, however only a few strains are implicated. These strains are usually found in animals with the majority in pigs. Other strains are also found in many other animals with lower frequency and they include rodents, rabbits, sheep, cattle, horses, dogs, and cats. In pigs, the bacteria are most likely to be found on the tonsils.
Yersinia enterocolitica is commonly present in foods but with the exception of pork, most isolates do not cause disease. Similarly to Listeria this organism is psychrotrophic meaning it can grow at refrigeration temperatures. Although rare, contamination in pasteurized milk has been documented and I’m surprised that it has not been included as an organism of interest in dairy companies around the world. The organism is sensitive to heat (5%) and acidity (pH 4.6), and will normally be inactivated by environmental conditions that will kill coliforms.
The illness caused by Yersinia entercolitica is called Yersiniosis and is common in children. Symptoms are similar to salmonella infection and include fever, abdominal pain, and diarrhea, which is often bloody. The symptoms appear 3 to 7 days after ingestion of the implicated food or exposure and may last up to 3 - 4 weeks.
In older children and adults, abdominal pain may occur predominantly on the right hand side and may be confused with appendicitis. In rare occurrences and in small proportion of cases, complications such as skin rash, joint pains or bacteria infection of the bloodstream can occur (sepecemia).
