Yersinia enterocolitica is a Gram-negative, mobile and ubiquitous bacterium, which causes enterocolitis in humans. It belongs to the genus Yersinia, the same as the causative agent of the plague (Yersinia pestis), fortunately disappeared from all over Europe.
Infection
The transmission of yersiniosis occurs by ingestion of water or food contaminated with faecal material, raw or undercooked, while the contagion through direct contact with infected animals or subjects (for example through blood transfusions from infected donors) is much rarer. Feature of Yersinia Enterocolitica is the resistance to low temperatures (it is a psychrophilic or cryophilic species, able to grow even at 4 ° C), which allows its development inside refrigerated foods. On the other hand, the heating of food to 60 ° C for a few minutes it kills the microorganism, but not its toxins, which are heat resistant.
Infections from Yersinia Enterocolitica cause the typical picture of gastroenteritis (watery diarrhea rich in mucus and pus, sometimes hemorrhagic, which can persist for one to three weeks, accompanied by fever and abdominal pain).
Symptoms and clinical forms
Symptoms typically arise after an incubation period of 4-7 days. The clinical manifestations of Yersinia enterocolitica in man they are however very heterogeneous, varying from paucisymptomaticity to the septicemic form.
While in animals yersiniosis generally has an asymptomatic course, in humans Yersinia enterocolitica it causes a variety of clinical pictures, due to the ability of the microorganism to invade many body tissues, in particular the mesenteric lymph nodes, causing mesenteric adenitis and terminal ileitis, which can be easily confused with acute appendicitis. The consequent dissemination by lymphatic route germs, explains the cases, albeit rare, of septicemia and purulent infections affecting various organs (central nervous system, liver and lungs). Some cases of yersiniosis are complicated by non-suppurative but inflammatory extraintestinal sequelae (especially reactive arthritis and erythema The most frequent clinical picture however remains acute enteritis or enterocolitis diarrhea, accompanied by fever or low-grade fever, crampy abdominal pain, and sometimes nausea and vomiting.
Diagnosis, prevention and treatment
The diagnosis of yersiniosis is made by direct examination of the faeces, considering that the isolation by coproculture is made difficult by the slow growth of Yersinia enterocolitica, which is why the tests are positive only after 7-14 days. Alternatively, seriological investigations are available for the search for antibodies directed against Yersinia enterocolitica, which appear early and disappear within 2-6 months.
The prevention of yersiniosis is dictated by common sense, and involves avoiding the consumption of meat, in particular pork, raw or undercooked, to consume only pasteurized milk, to respect adequate hygiene rules in contact with animals, to prevent cross - contamination during food preparation (wash your hands after handling raw meats, do not reuse the same tools used to process raw meats before washing them, keep raw meats separate from cooked ones), in addition to adequate disposal of sewage of animal origin.
The yersiniosis generally proceeds in a self-limiting manner, so the treatment is limited to the rehydration of the patient and to the possible correction of electrolyte alterations and of the acid-base balance. Any antibiotic therapy is undertaken in complicated cases (septicemia, focal infections, active antibiotics against Yersinia enterocolitica we remember doxycycline, trimethoprim-sulfamethoxazole, fluoroquinolones, ceftriaxone and chloramphenicol.
