definition
Yersinia enterocolitica and Yersinia pseudotuberculosis are the primary causative agents of yersiniosis, a zoonotic infectious disease.
Both Y. enterocolitica and Y. pseudotuberculosis are Gram-negative, small, rod-shaped, non-spore-forming, facultative anaerobic bacteria belonging to the Yersiniaceae family.
While the majority of cases are sporadic, notable outbreaks have been reported in the USA, Canada, Japan, and Europe.
These bacteria are psychrotrophic, meaning they can grow at temperatures below 4°C. Specifically:
In addition, Y. enterocolitica can produce a thermostable toxin under cooling conditions (4–8°C).
Both Y. enterocolitica and Y. pseudotuberculosis are capable of growing at pH values between approximately 4.0 and 10.0, with an optimum pH of around 7.6.
Y. enterocolitica is classified into six biotypes based on its biochemical characteristics, and it exhibits numerous serotypes determined by the O antigen. However, only specific combinations of biotypes and serotypes are associated with infections in both humans and animals. The most frequently reported bioserotype in the EU is 4/O:3, followed by 2/O:9. Non-pathogenic bioserotypes, which lack the virulence plasmid and other genes crucial for pathogenesis, are widespread and are the most common types isolated from food and the environment. [1]
In contrast to Y. enterocolitica, all strains of Y. pseudotuberculosis are uniformly classified as pathogenic, due to the ubiquitous presence of the virulence plasmid and virulence genes. Y. pseudotuberculosis is categorised into 15 O-serotypes: serotype I is by far the most commonly associated with human and animal infections followed by serotype III.
Y. enterocolitica and Y. pseudotuberculosis strains are typically susceptible to most antimicrobials used to treat humans and animals. However, there is an increasing prevalence of multidrug-resistant Y. enterocolitica strains, particularly in food and the environment, which poses a growing risk to both human and animal health. Additionally, Y. enterocolitica exhibits intrinsic resistance to certain antibiotics, including β-lactams.[1]
food matrices
