Yersiniosis

Yersiniosis is infection by Yersinia enterocolitica or Y. pseudotuberculosis, acquired by eating contaminated pork, milk, vegetables or water, or by transfusion of contaminated blood. Y. enterocolitica favours cold environments, and the organism multiplies at 4 degrees Celsius.

• Children are most affected; adults develop post infectious arthritis and erythema nodosum.
• Iron overload (thalassaemia, haemochromatosis, deferoxamine therapy), diabetes, cirrhosis and immunosuppression predispose to septicaemia.

Incubation 4 to 7 days, then fever, abdominal pain (often right lower quadrant), and watery or bloody diarrhoea lasting 1 to 3 weeks.

• Terminal ileitis and mesenteric adenitis mimic appendicitis (pseudoappendicitis); pharyngitis.
• Septicaemia causes high fever, metastatic abscess (liver, spleen), and high mortality.
• Differential diagnosis: appendicitis, Crohn disease, campylobacteriosis, salmonellosis, shigellosis, intestinal tuberculosis, amoebiasis, typhoid, lymphoma.
• Complications: bacteraemia, hepatosplenic abscess, erythema nodosum, reactive arthritis, Reiter syndrome, thyroiditis, glomerulonephritis, perforation, intussusception.

Culture and molecular tests.

• Stool culture on cefsulodin irgasan novobiocin agar with cold enrichment (4 degrees Celsius for 2 to 3 weeks); multiplex PCR; blood culture in febrile patients; culture of mesenteric nodes or surgical specimens.
• Serology for post infectious complications; HLA B27 in reactive arthritis.
• Ultrasound or CT: ileal wall thickening and mesenteric adenopathy.
• Full blood count, CRP, iron studies in septicaemia.

Supportive care for self limiting enterocolitis; antibiotics for severe or invasive disease.

• Supportive: oral rehydration solution, fluids, analgesia (paracetamol 1 g four times daily), avoidance of antimotility drugs, reassure that surgery is not needed for mesenteric adenitis, stop iron and deferoxamine therapy temporarily in septicaemia.
• Pharmacological: cotrimoxazole 960 mg twice daily for 5 days (children trimethoprim 4 mg/kg twice daily) or ciprofloxacin 500 mg twice daily for 5 days for severe enterocolitis in adults. Septicaemia or focal disease: ceftriaxone 2 g IV daily (children 80 mg/kg daily) plus gentamicin 5 mg/kg IV daily or ciprofloxacin 400 mg IV every 12 hours, for 2 to 3 weeks, longer for abscess. Reactive arthritis: ibuprofen 400 mg three times daily; antibiotics do not alter its course.
• Procedures: drainage of abscess; appendicectomy only if appendicitis is confirmed.
• Special groups: pregnancy, ceftriaxone or azithromycin and avoidance of fluoroquinolones; children, cotrimoxazole or cefotaxime; iron overload, early parenteral therapy; HIV, extended treatment.
• Red flags: high fever with rigors, jaundice, hepatic abscess, peritonism, painful rash with joint swelling, immunosuppression.
• Follow-up: review at 1 week; repeat imaging for abscess after 2 weeks; monitor joint symptoms for 3 months.