Yersinia Selective Agar- Composition, Principle, Preparation, Results, Uses


Yersinia enterocolitica is a gram-negative, bacillus-shaped bacterium that belongs to the family Yersiniaceae. It is one of the three pathogenic species of the genus Yersinia, along with Y. pestis and Y. pseudotuberculosis.

Y. enterocolitica causes yersiniosis, a zoonotic disease that affects humans and various animals, such as pigs, cattle, deer, and birds. The infection can manifest as acute diarrhea, mesenteric adenitis, terminal ileitis, and pseudoappendicitis. In rare cases, it can also cause sepsis.

Y. enterocolitica is widely distributed in nature and can be found in various reservoirs, such as the intestinal tracts of mammals, avian species, cold-blooded species, and environmental water. However, not all strains of Y. enterocolitica are pathogenic for humans. The pathogenic strains are classified into six biogroups (1B and 2-5) and more than 57 serogroups based on their phenotypic and antigenic characteristics.

The most common serogroups associated with human disease are O:3 (biogroup 4), O:5,27 (biogroups 2 and 3), O:8 (biogroup 1B), and O:9 (biogroup 2). The serogroup distribution varies geographically; for example, serogroup O:3 is predominant in Europe, while serogroup O:8 is more prevalent in the United States.

The isolation and identification of Y. enterocolitica from clinical specimens and food samples can be challenging due to its low infectious dose, slow growth rate, and similarity to other enteric bacteria. Therefore, selective media and enrichment procedures are often used to enhance its recovery and differentiation.