ABSTRACT
Yersinia enterocolitica and Yersinia pseudotuberculosis are pathogenic bacteria that cause foodborne diseases classified by the International Commission on Microbio-logical Specifications for Foods in risk group II: “diseases of serious hazard, incapacitating but not life threatening, of moderate duration with infrequent sequelae.” Y. enterocolitica is a heterogeneous species, the strains of which can be subdivided into biotypes and serotypes. According to the 2nd Edition of Bergey’s Manual of Systematic Bacteriology, Yersinia is a genus of the family Enterobacteriaceae and are defined as rod-shaped to coccobacilli, Gram-negative bacteria. They are facultative anaerobes, oxidase negative, catalase positive, and, usually, urease and nitrate positive. They ferment glucose with little or no gas production and are psychrotrophic in nature, with an optimal growth temperature between 28°C and 29°C. According to the Food and Drug Administration, Y. enterocolitica is not part of the normal human flora, but has been isolated from feces, wounds, sputum and mesenteric lymph nodes of humans.
