Continuing Education Activity
To improve patient health outcomes, clinicians need to recognize that Yersinia enterocolitica has a form of acute diarrheal infection as well as a pseudoappendicitis that mimics appendicitis (both require different treatment strategies). This activity reviews the evaluation and management of Yersinia enterocolitica Recombinant and highlights the role of the interprofessional team in the recognition and management of this condition.
- Discuss the recommended management of Yersinia enterocolitis.
- Outline the typical presentation (acute yersiniosis and pseudoappendicitis) of a patient with yersinia enterocolitica.
- Review the pathophysiology of Yersinia enterocolitis.
- Explain the strategies of the interprofessional team to improve care coordination and communication in the management of patients with yersinia enterocolitica.
Yersinia enterocolitica is a rod-shaped, gram-negative bacterium that causes a zoonotic disease called yersiniosis. The infection manifests as acute diarrhoea, mesenteric adenitis, terminal ileitis, and pseudoappendicitis. In rare cases, it can even cause sepsis.
In some countries, yersinia infections have overtaken shigella and salmonella species as the most common cause of bacterial gastroenteritis. While most cases are sporadic, large outbreaks are not uncommon. Humans acquire yersinia after consumption of contaminated food, as well as from a blood transfusion. The key feature of yersinia is that the individual will continue to shed the organism in the faeces for nearly 3 months after symptoms have abated; therefore, detection of yersinia in faeces is essential.
The genus Yersinia includes 11 species, of which 3 stand out for causing diseases in humans: Yersinia pestis, Yersinia enterocolitica and Yersinia pseudotuberculosis. Yersinioses are zoonotic infections of humans that are incidental hosts that do not contribute to the life cycle of the pathogen. Yersinia is classified according to its biochemical characteristics and of the 6 biotypes, subtypes 2, 3 and 4 are the most common in humans.
Y. enterocolitis has been isolated from a variety of animals, with pigs being the most common source. The pathogen can spread from pig to pig in a herd. The insect can contaminate pork products, including cuts from the neck, tongue, and tonsils, and can spread to other cuts of meat during slaughter.
Yersinia is classified according to its phenotype and serotype. Phenotypically, these insects are divided into 6 groups, of which 5 (1B and 2-5) are considered pathogens. Based on serotyping, this pathogen is classified into more than 57 serogroups O. However, only a few of these are pathogenic. The pathogenic serotypes are O:3 (group 4), O:5,27 (group 2 and 3), O:8 (group 1B) and O:9 (group 2). The most common serogroup isolated from humans in European countries is O:3 followed by O:9. In the United States, serogroup O:8 is more common.
The infection is transmitted predominantly by the faecal-oral route. The consumption of pork, especially raw or undercooked pork products, is responsible for yersiniosis. Outbreaks have also been reported in Norway and New Zealand from untreated drinking water contaminated with this pathogen. There are case reports of infection being transferred from an infected household pet and through transfused blood products.
The pathogen passes to the stomach, crosses the intestinal wall and is localized in the lymphoid tissue and mesenteric lymph nodes. The bacterium has a virulent 70 kilodalton plasmid known as per which is present in pathogenic Yersinia species including enterocolitis, pestis and pseudotuberculosis. The bacteria also produce ureases that metabolize urea and form ammonia to protect themselves from the harsh acidic environment of the stomach.
Bacteria also produce Ail (junctional invasion focus) and YadA, which confers resistance to complement-mediated opsonization and prevents phagocytosis. The bacterium also contains Yops (Yersinia outer membrane proteins) which stops phagocytosis by blocking the secretion of mediators including TNF-alpha and IL-8. Certain strains produce yersiniabactin, which is an iron-binding agent that can effectively bind iron in a depleted state. This further allows bacteria to thrive and grow.
History and Physique
Yersinia infections can present with enterocolitis, pseudoappendicitis, reactive arthritis, sepsis, pharyngitis, myocarditis, mesenteric adenitis, or dermatitis. Clinically, the infection can manifest itself in 2 ways:
- Acute yersiniosis
This condition manifests as diarrhoea, abdominal pain, nausea, vomiting, and fever. The duration of diarrhoea can vary from 12 to 22 days. Yersiniosis is difficult to distinguish from other causes of acute diarrhoea because of the similar presentation. The location of pain in the right lower quadrant may be a diagnostic clue for yersiniosis. Bloody diarrhoea is seen more often in children than in adults. Sepsis has been described in infants and immunocompromised or iron overload patients with an overall mortality rate of 50 per cent. After acute infection, the bacteria can continue to be shed in the faeces for a median of 40 days (range 17 to 116 days).
Acute yersiniosis can mimic appendicitis and present with right lower quadrant abdominal pain, fever, vomiting, elevated white blood cell count, and diarrhoea. Patients brought for surgery show swelling of the terminal ileum and mesenteric lymph node with a normal appendix. Pseudoappendicitis is more common in young children and in many cases results in an appendectomy.
Reactive arthritis can also occur after yersinia and tends to affect multiple joints. The larger joints are often involved, and symptoms can last 30 to 120 days. In most cases, joint symptoms appear 7 to 14 days after gastrointestinal symptoms. Another characteristic of yersinia is erythema nodosum with lesions appearing 2 to 14 days after abdominal pain. The lesions are more common in adult women and usually resolve on their own.
Treatment / Management
Yersinia treatment is supportive care with hydration and nutritional support. The drugs of choice are aminoglycosides or trimethoprim-sulfamethoxazole. Other effective agents include tetracycline (not in children), quinolones, and cephalosporins. Surgery is sometimes required to drain an abdominal abscess, and surgical exploration is warranted if appendicitis cannot be ruled out. It is important to note that in many cases, pseudoappendicitis and appendicitis cannot be differentiated on clinical examination or even imaging. Therefore, some patients undergo surgery to remove an appendix.
In such scenarios, the appendix is normal, but there are localized mesenteric adenitis, which is confirmed by the pathologist. Antimotility agents should be avoided in patients with diarrhoea as they may worsen the infection. Antibiotics should be used only in selected patients, such as the elderly, immunosuppressed people, or patients with diabetes. Children may require hospitalization for dehydration or sepsis. Most patients are anorexic and may require overnight hospitalization for intravenous (IV) hydration. In some cases, patients are admitted because appendicitis cannot be ruled out.
Preventive measures include handwashing after exposure to an exposed animal, safe food processing, avoiding consumption of raw pork and produce, routine water treatment and disinfection, and screening for the pathogen in blood and blood products.
Diagnosis depends on a detailed history, detailed physical examination, and supporting laboratory and radiological findings. Diseases that can present in a similar way include:
- Acute diarrhoea (secondary viral, bacterial, protozoan, fungal organisms)
- inflammatory bowel disease
- drug-associated colitis
- ischemic colitis
- HIV, influenza, dengue, malaria (developing countries)
- radiation colitis
- Shunt colitis
- Solitary rectal ulcer syndrome
- Colon cancer, small intestine