YersiniosisA04.6

The collective term Yersiniosis is used to describe infections caused by bacteria of the genus Yersinia.

In Germany and throughout Europe, Y. enterocolitica strains of bioserovar 4/O:3 are the most common pathogen causing yersiniosis (approx. 90% of transmitted yersinioses with information on the serovar), with bioserovar 2/O:9 being the second most common (approx. 7%). Bioserovar 1B/O:8, which is endemic in North America, can cause particularly severe courses of the disease. It occurs rarely in Germany and Europe (mostly travel-associated).

Within the Y. pseudotuberculosis species, 21 different serotypes and subtypes are currently distinguished. In addition to Y. pseudotuberculosis sensu stricto, the Y. pseudotuberculosis complex also includes the newer species Y. similis and Y. wautersii, about whose human pathogenicity not much is yet known.

Oral transmission through contaminated, insufficiently heated meat(60% of cases) via contaminated water and animal contact. Zoonosis (indirectly from animals via food, dairy products, raw pork) (Tauxe RV 2004). The pathogens can also multiply at low ambient temperatures (refrigerator temperature) and under microaerophilic conditions. Pigs (domestic pigs and wild boar) are the most important animal reservoir for the human pathogenic Y. enterocolitica strains. The infection is asymptomatic here. Carcasses can therefore be contaminated during the slaughter process (Drummond N et al. 2012). Y. pseudotuberculosis is widespread in the environment and is mainly isolated from various birds and wild animals, e.g. rodents and other small mammals.

Y. enterocolica can also be transmitted by blood transfusion.

Infectivity lasts as long as the symptoms persist, usually 2-3 weeks. A longer shedding period is possible in both children and adults.

Worldwide occurrence; incidence in Germany approx. 3/100,000/year, most frequently in children < 5 yrs. Yersinia enterocolitica is detectable in approx. 1% of all diarrheal diseases (peak January). The majority of transmitted yersinioses (about 98%) occur as sporadic cases in Germany. Most outbreaks affect private households and comprise 2-4 cases.

Yersiniosis is much more common in Eastern Europe and Russia.

Incubation period: Usually 3-7 days, rarely more than 10 days.

Gastroenteritis (young children): Pseudoappendicitis (older children, adolescents): Appendicitis-like symptoms with mesenteric lymphadenitis (Maßhoff's disease, Maßhoff's lymphadenitis, pseudoappendicitis).

Enterocolitic course: Onset acute often with colicky lower abdominal pain, watery diarrhea (especially in young children), fever, headache, nausea and vomiting.

Pathogen detection: Culturally from stool, mesenteric lymph nodes (after surgery), intestinal biopsies, blood (in sepsis), possibly also detection of Yersinia DNA. Yersinia can still multiply on meat and sausage at + 4°C in the refrigerator. In rare cases Y. enterocolitica can be transmitted by blood transfusion).

Serology: Twofold titer determination for antibodies against Y. enterocolitica O:3 and O:9 as well as Y. pseudotuberculosis.

If antibodies against Y. enterocolitica O:9 are found in negative stool findings, brucellosis must be excluded as a differential diagnosis, since there is a cross-antigenicity between Brucella and the Y. enterocolitica serotype O:9.

When reactive arthritis occurs, serological detection of Yop (yersinia outer protein) antibodies is used for diagnosis. Yop-positive diagnoses are only meaningful if a titer increase can be detected between two samples taken several days apart.

Immunopathological complications occur in up to 20 % of cases. These occur more frequently in HLA-B27-positive patients (w>m) and are usually symptoms of rheumatoid arthritis, e.g. reactive arthritis, (peri-)carditis, erythema nodosum, acute glomerulonephritis.

Rare are exanthema reminiscent of pityriasis lichenoides acuta (Yotsu R et al. 2010); Zińczuk J et al. 2015; Touraud JP et al. 2000).

Liver abscesses with a septic course and inflammation of various organs (pericardium, pleura, skin, etc.) have been described in rare cases, particularly in the case of underlying diseases with reduced resistance.

Another rare complication is pyomyositis (PM), a primary bacterial infection of the skeletal muscle caused by hematogenous spread or injury to the muscle. The affected muscle is painful and sensitive to pressure. Abscess formation is possible.

During the duration of the illness, patients should stay at home and observe the listed hygiene measures. For infections in hospitals, other medical facilities, homes, care facilities and other community facilities, special hygiene measures apply.

In mild cases: In the case of an acute Yersinia infection without a severe course of the disease, antimicrobial therapy should not normally be used, as the course of the disease cannot be significantly influenced, in accordance with the S2k guideline "Gastrointestinal infections and Whipple's disease" (Hagel et al., 2015). Oral fluid and electrolyte substitution are sufficient.

In severe cases: antibiotic therapy with fluoroquinolones (e.g. ciprofloxacin) or 3rd generation cephalosporins (e.g. ceftriaxone)

Mostly healing without consequences

Obligation to register with a doctor according to IfSGMeldeVO (only in Saxony): Obligation to register by name in case of illness and death as well as persistent excretion of Yersinia enterocolitica with the stool.

Duty to report to the laboratory according to § 7 IfSG: Duty to report by name in case of pathogen detection of intestinal pathogenic Yersinia spp.

In the Swiss Animal Diseases Act, yersiniosis is included in the list of epidemic diseases to be monitored.

1. Bundesinstitut für Risikobewertung (BfR): Yersinien in Lebensmitteln: Empfehlungen zum Schutz vor Infektionen. BfR Opinion No 002/2013 of 18 January 2013(www.bfr.bund.de).
2. Drummond N et al. (2012) Yersinia enterocolitica: a brief review of the issues relating to the zoonotic pathogen, public health challenges, and the pork production chain. Foodborne Pathog Dis 9:179-189.
3. Hagel S et al (2015) S2k guideline Gastrointestinal infections and Whipple's disease. Z Gastroenterol 53:418-459
4. Kato H et al. (2016) Primary cellulitis and cutaneous abscess caused by Yersinia enterocolitica in an
   immunocompetent host: A case report and literature review.Medicine (Baltimore) 95:e3988.
5. Long C et al. (2010): Yersinia pseudotuberculosis and Y. enterocolitica infections, FoodNet, 1996-2007. Emerg Infect Dis 16:566-567.
6. Tauxe RV (2004) Salad and pseudoappendicitis: Yersinia pseudotuberculosis as a foodborne pathogen. J Infect Dis 189:761-3
7. Touraud JP et al (2000) Cutaneous manifestations of Yersinia enterocolitica infection. Ann Dermatol Venereol 127(8-9):741-744.
8. Yotsu R et al (2010) Erythema nodosum associated with Yersinia enterocolitica infection. J Dermatol 37:819-822.
9. Zińczuk J et al (2015) Mesenteric lymphadenitis caused by Yersinia enterocolitica. Prz Gastroenterol 10:118-121.