Description

Yersinia enterocolitica is a gram-negative bacillus that produces an enteric infection characterized by fever, diarrhea, and abdominal pain that may mimic acute appendicitis.

Epidemiology

• According to surveillance by the Foodborne Diseases Active Surveillance Network (FoodNet) from 2015, the annual incidence of Y. enterocolitica infections was 0.28 per 100,000 persons.
• 16% of infections occurred in children <5 years, and almost 30% occurred in children <19 years.
• Transmission of Y. enterocolitica
  • Occurs through ingestion of contaminated food or water (particularly raw or undercooked pork or unpasteurized milk products) or contact with infected animals (swine are the principal reservoir)
  • Fecal–oral and person-to-person transmission are also possible.
  • In the United States, most epidemics have been related to the improper handling of raw pork intestine (chitterlings), most often during winter holiday festivities among African American households in the South.
  • Transmission to young children occurs through contact with adult caregivers preparing the chitterlings.
• Transmission through transfusion of contaminated blood products is also possible. The U.S. Food and Drug Administration (FDA) has reported that contamination of the U.S. blood supply by bacteria, although rare, is most frequently due to Y. enterocolitica.
• The incubation period is ~1 to 14 days (average 4 to 6). The mean duration of organism excretion is 42 days; however, asymptomatic carriage can persist even longer.
• Systemic disease or bacteremia occurs more commonly in young infants or those with predisposing conditions, including:
  • A clinical state of iron overload or deferoxamine therapy
  • Immunosuppression
  • Diabetes mellitus
  • Malnutrition
  • Cirrhosis or other liver diseases

General Prevention

• Infection control
  • Contact precautions are indicated for patients with enterocolitis until diarrhea resolves.
• General measures
  • Attempts to eliminate reservoirs and reduce frequency of ingesting contaminated foods and beverages are necessary.
  • Ingestion of undercooked meats, especially pork and unpasteurized milk, should be avoided.
  • Meticulous hand hygiene before and after handling uncooked meat products and avoidance of preparation of meats near or during preparation of infant bottles for feeding are essential.

Pathophysiology

• The portal of entry for Y. enterocolitica is the gastrointestinal tract.
• Y. enterocolitica adheres to epithelial cells and mucus, producing heat-stable enterotoxins, which play a role in the development of watery diarrhea.
  • Another cytotoxin then directly injures the distal small and large bowel, producing stools characterized by blood and mucus.
  • Release of these toxins leads to the development of an enterocolitis, most commonly in younger age groups.
• Mesenteric adenitis and/or terminal ileitis may lead to a pseudoappendicitis syndrome, typically in the older child or young adult.
• Bacteremia may lead to focal abscesses in a variety of organs, including the lung, liver, spleen, and kidney.

Etiology

• The genus Yersinia consists of 11 species, of which Y. enterocolitica, Yersinia pseudotuberculosis, and Yersinia pestis are the three most commonly encountered pathogens.
• Y. enterocolitica is a facultative, non–lactose-fermenting, urease-positive, gram-negative bacillus.
• >60 serotypes and six biotypes of Y. enterocolitica have been identified. Serotypes O:3, O:5.27, O:8, and O:9 and biotypes 2, 3, and 4 are most commonly isolated from patients. Serotype O:3 is the most common type in the United States.