Yersinia enterocolitica (Y. enterocolitica) is a Gram-negative bacteria belonging to Enterobacteriaceae group since 60’s. Basing on specific biochemical and serological characteristics there where isolated serological types and biotypes of Yersinia enterocolitica. Most widespread of these are biotypes 1B, 2, 4 and belonging to them respectively serotypes O:8, O:9, O:3. Among them, the most frequent pathogen is serotype O:3. Currently, in Poland and other European countries, there is notified growth in number of infections caused by highly virulent serotype O:8 till now appearing only in USA. Yersinia causes zoonosis called yersiniosis. Contaminated food infects human. Clinical appearance of yersiniosis varies depending on bacterial virulence, age and immunological status of ill patient. Usually disease appears as mild enterocolitis. Yersinia together with Campylobacter pylori and Salmonella is the most frequent bacterial factor causing enterocolitis in Europe. In state of immunological deficiency infection with Yersinia can cause severe purulent complications and highly mortal sepsis. The source of serotype O:8 infections in Poland is still not found. It has been isolated on the territory of whole country, from ill people in different age and with different clinical picture of yersiniosis. Serological and microbiological methods are used in diagnostic process of yersiniosis. Both of this are not perfect and should cover each other. Because of unclear epidemiological status of Yersinia enterocolitica type O:8 in Poland, if this infection is suspected, there is a duty to send probes of infected material and serum, together with detailed interview to Instytut Bakteriologii Państwowego Zakładu Higieny. There is serotyping processed and virulence factors estimated. As important as diagnosis is promotion of preventive actions like sanitary principles or avoidance of eating of uncooked food.

yersiniosis, zoonoses, enterocolitis, enterotoxin, pseudoapendicitis, sepsis