Yersinia pseudotuberculosis: Infection, Symptoms & Treatment

What is Yersinia pseudotuberculosis?

Yersinia pseudotuberculosis is a gram-negative, rod-shaped bacterium belonging to the family Enterobacteriaceae and the genus Yersinia. This genus also includes Yersinia pestis, the causative agent of plague, and Yersinia enterocolitica, a common cause of diarrheal disease. The name refers to the ability of the bacterium to produce tuberculosis-like changes in lymph nodes, although it is biologically unrelated to the tuberculosis pathogen Mycobacterium tuberculosis.

Causes and Routes of Transmission

Infection with Yersinia pseudotuberculosis typically occurs through the consumption of contaminated food or water. Animal feces, particularly from rodents, birds, and domestic pets, are common sources of contamination. A notable characteristic of this bacterium is its ability to multiply at refrigerator temperatures -- a property known as psychrotrophism.

• Contaminated food (raw meat, vegetables, water)
• Direct contact with infected animals or their excretions
• Fecal-oral transmission between humans (rare)
• Insufficiently cooked animal products

Symptoms

The most characteristic clinical presentation is mesenteric lymphadenitis -- inflammation of the abdominal lymph nodes -- which can closely mimic acute appendicitis. Common symptoms include:

• Abdominal pain, often in the lower right quadrant
• Diarrhea (sometimes bloody)
• Nausea and vomiting
• Fever
• General malaise and fatigue

In rare cases, especially in immunocompromised individuals, the infection can lead to sepsis or dissemination to other organs. Late complications such as reactive arthritis or erythema nodosum (tender skin nodules) have also been reported.

Diagnosis

Diagnosis is typically confirmed through microbiological testing. The following methods are used:

• Stool culture: Isolation of the pathogen from fecal samples
• Blood culture: Used when sepsis is suspected
• Serology: Detection of antibodies against Yersinia pseudotuberculosis in the blood
• PCR (polymerase chain reaction): Molecular identification of the bacterium
• Imaging: Abdominal ultrasound or CT scan to assess lymph node enlargement

Treatment

In otherwise healthy individuals, the infection is usually self-limiting and resolves without specific treatment. In severe cases or in high-risk patients, antibiotic therapy is required. Yersinia pseudotuberculosis is generally susceptible to:

• Fluoroquinolones (e.g., ciprofloxacin)
• Trimethoprim-sulfamethoxazole (TMP-SMX)
• Aminoglycosides (e.g., gentamicin)
• Third-generation cephalosporins

Supportive measures such as adequate fluid intake and pain relief are used as needed. Suspected sepsis requires immediate hospitalization and intravenous antibiotic therapy.

Prevention

The following hygiene measures are recommended to reduce the risk of Yersinia pseudotuberculosis infection:

• Thorough handwashing after animal contact and before eating
• Adequate cooking of meat and other animal products
• Safe food handling practices (avoiding cross-contamination)
• Drinking clean, treated water
• Regular cleaning and disinfection of refrigerators

References

1. World Health Organization (WHO): Zoonoses and the Human-Animal-Ecosystems Interface. WHO, Geneva, current edition.
2. Bottone EJ. Yersinia enterocolitica and Yersinia pseudotuberculosis. In: Murray PR et al. (eds.): Manual of Clinical Microbiology. ASM Press, Washington D.C.
3. Prentice MB, Rahalison L. Plague. Lancet. 2007;369(9568):1196-1207. (Context: Yersinia genus overview and pathogenicity mechanisms.)