Yersinia pseudotuberculosis

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Yersinia pseudotuberculosis
Systematics
Department : Proteobacteria
Class : Gammaproteobacteria
Order : Enterobacterales
Family : Enterobacteriaceae
Genre : Yersinia
Type : Yersinia pseudotuberculosis
Scientific name
Yersinia pseudotuberculosis
( Pfeiffer 1889) Smith & Thal 1965

Yersinia pseudotuberculosis is a pathogenic gram-negative bacterium from the genus Yersinia . The pathogen primarily affects animals, especially rodents , rabbits and wild birds . Humans can also be infected, mostly through contaminated food or water; thedisease causedby Y. pseudotuberculosis is thus a zoonosis . Infections through contact with pets do not play a major role.

history

The disease caused by the pathogen was first described in guinea pigs in 1883 . In 1889 Pfeiffer isolated the pathogen and named it Bacillus pseudotuberculosis . Molaret assigned the bacterium to the Yersinia in 1966.

properties

Y. pseudotuberculosis is a 1.5–6 × 0.4–0.8 µm large bacterium with varying shapes. It is flagellated and mobile at room temperature. It does not form spores and grows in the presence of oxygen (aerobic). Y. pseudotuberculosis has a lot in common with Y. pestis , the causative agent of the plague , the latter was also considered a subspecies of Y. pseudotuberculosis for a while. Biochemically , both pathogens behave in almost the same way, so that a differentiation via the Bunte series is not possible.

There are 20 different O antigens and 5 different H antigens. From their combination, 11 serogroups of Y. pseudotuberculosis are differentiated. In Germany only the serotypes O: 1, O: 2 and O: 3 are common. All strains are fundamentally pathogenic to humans and many animal species. Serotype 1 is predominantly found in infections in Europe, followed by serotype 3.

The bacterium is relatively resistant to environmental influences and can multiply in water at temperatures above 18 degrees Celsius. Y. pseudotuberculosis remains infectious in the soil for many months. All conventional culture media , especially blood agar, are suitable for cultivation .

The pathogen has a broad host spectrum. Rodents , rabbits and wild birds are considered reservoirs . You excrete the pathogen with the feces .

Infection in humans

Classification according to ICD-10
A28.8 Other specified bacterial zoonoses, not elsewhere classified
ICD-10 online (WHO version 2019)

In humans, Y. pseudotuberculosis, along with Yersinia enterocolitica , the main reservoir of which is mainly domestic pigs , causes yersiniosis . Wild animals are probably the most important reservoir in Europe for Y. pseudotuberculosis , but the pathogen is also found in untreated surface water. Vegetables can also be contaminated with Y. pseudotuberculosis through direct contact with wild animal droppings or through contaminated water . Little is known about the spread of Y. pseudotuberculosis in food because foods are not routinely screened for Y. pseudotuberculosis . Growing Y. pseudotuberculosis from food and environmental samples is very difficult.

Eating foods contaminated with Y. enterocolitica and Y. pseudotuberculosis can cause a food infection. The incubation period is one to two weeks. The infection leads to diseases of the small intestine with involvement of the lymph nodes . Especially children and young people develop as well as by Yersinia enterocolitica caused a mesenteric lymphadenitis (Crohn Maßhoff, Maßhoff-lymphadenitis) with acute terminal ileitis (so-called. Pseudoappendicitis). The clinical picture can appear with the signs of inflammation of the intestine ( enteritis ), as apparent appendicitis or with the symptoms of Crohn's disease ("Pseudocrohn").

The pathogens are excreted for two to ten weeks. Reiter's disease can develop as a secondary illness , especially in HLA-B27- positive patients. Yersinia antibodies act against the body's own tissue .

Infection in animals (rodentiosis, pseudotuberculosis, rodent tuberculosis)

In rodents, rabbits, dogs and birds, the pathogen can cause symptoms similar to tuberculosis . Guinea pigs and rats (“ rodentiosis ”, rodents = rodentia ), rabbits and turkeys are particularly susceptible . But also in chinchilla , nutria , rabbit , fox , mink , domestic fowl , canary and deer , Y. pseudotuberculosis can cause symptoms similar to tuberculosis. The term “pseudotuberculosis” should be avoided, as it has a double connotation with pseudotuberculosis in sheep and goats (pathogen: Corynebacterium pseudotuberculosis ). The term “rodent tuberculosis” is also misleading as the disease is not caused by mycobacteria .

The infection occurs orally , in predators mostly by ingesting infected rodents, in the others via food contaminated with faeces. The pathogen forms focal lesions in the intestine and spreads through the blood vessel system in the body, causing septicemia with swelling of the spleen . Here, susceptible animals can already die from circulatory failure. Such acute disease courses are particularly evident in turkeys that die within a few days with severe general disorders (shortness of breath, skin discoloration, lameness).

If the septicemia is overcome, tuberculosis-like foci develop in internal organs (spleen, liver , kidney , lungs , lymph nodes ), whereby the enlarged lymph nodes can be palpated through the abdominal wall . This subacute form is the rule in rodents, rabbits and birds; the animals die after 2 to 3 weeks with emaciation and paralysis.

The classic domestic mammals (dogs, cats, sheep, goats, cattle, pigs) and ornamental birds can, but only very rarely, suffer from subacute diarrheal diseases with emaciation and jaundice . The disease is so unspecific that the diagnosis is usually made in the pathology department. Even as the causative agent of pneumonia and ruminants of mastitis and abortion was Y. pseudotuberculosis isolated.

Combat

For therapy , the most suitable in animals broad-spectrum antibiotics , such as a long term treatment with chloramphenicol . However, the therapy is often unsuccessful. In the case of guinea pigs, the treatment is almost futile; infected animals should be killed here.

Consistent rodent control is recommended for prophylaxis. Zoo animals such as monkeys or birds can be vaccinated .

literature

  • Federal Institute for Risk Assessment (BfR): Yersinia in food: Recommendations for protection against infections . Opinion No. 002/2013 of January 18, 2013
  • H.-J. Selbitz: Yersinia . In A. Rolle and A. Mayr (eds.): Medical microbiology, infection and epidemic theory . Enke, Stuttgart, 7th edition 2001. ISBN 3-432-84686-X

Web links

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