<unk>  is a Gram-negative, bacillus-shaped bacterium, belonging to the family<unk> rsiniaceae. It is motile at temperatures of 22–29°C (72–84°F), but becomes nonmotile at normal human body temperature.<unk>  infection causes the disease<unk> rsiniosis, which is an animal-borne disease occurring in humans, as well as in a wide array of animals such as cattle, deer, pigs, and birds. Many of these animals recover from the disease and become carriers; these are potential sources of contagion despite showing no signs of disease. The bacterium infects the host by sticking to its cells using trimeric autotransporter adhesins. The genus<unk> rsinia includes 20 species: Y. aldovae, Y. aleksiciae, Y. bercovieri, Y. canariae,<unk> , Y. entomophaga, Y. frederiksenii, Y. hibernica, Y. intermedia, Y. kristensenii, Y. massiliensis, Y. mollaretii, Y. nurmii, Y. pekkanenii, Y. pestis, Y. pseudotuberculosis, Y. rohdei, Y. ruckeri, Y. similis, and Y. wautersii. Among them, only Y. pestis, Y. pseudotuberculosis, and certain strains of<unk>  are of pathogenic importance for humans and certain warm-blooded animals, whereas the other species are of environmental origin and may, at best, act as opportunists. However,<unk> rsinia strains can be isolated from clinical materials, so they have to be identified at the species level.<unk>  is a heterogeneous group of strains, which are traditionally classified by biotyping into six biogroups on the basis of phenotypic characteristics, and by serotyping into more than 57 O serogroups, on the basis of their O (lipopolysaccharide or LPS) surface antigen. Five of the six biogroups (1B and 2–5) are regarded as pathogens. However, only a few of these serogroups have been associated with disease in either humans or animals. Strains that belong to serogroups O:3 (biogroup 4), O:5,27 (biogroups 2 and 3), O:8 (biogroup 1B), and O:9 (biogroup 2) are most frequently isolated worldwide from human samples. However, the most important<unk>  serogroup in many European countries is serogroup O:3 followed by O:9, whereas the serogroup O:8 is mainly detected in the United States.<unk>  is widespread in nature, occurring in reservoirs ranging from the intestinal tracts of numerous mammals, avian species, cold-blooded species, and even from terrestrial and aquatic niches. Most environmental isolates are avirulent; however, isolates recovered from porcine sources contain human pathogenic serogroups. In addition, dogs, sheep, wild rodents, and environmental water may also be a reservoir of pathogenic<unk>  strains. Human pathogenic strains are usually confined to the intestinal tract and lead to enteritis/diarrhea.
Yersinia enterocolitica
Campylobacter jejuni
Campylobacter upsaliensis
Yersinia rohdei
Yersinia pseudotuberculosis
Enteroaggregative Escherichia coli
Clostridioides difficile 
Vibrio cholerae