Abstract:
Enterobacteria represent a diverse family of Gram-negative bacilli that are typically associated with the gastrointestinal
tract of humans and animals, where they can act as commensals or pathogens. Among them, the genus Yersinia includes
19 species, with Y. enterocolitica and Y. pseudotuberculosis recognized as significant enteric pathogens, while Y. pestis
causes plague. Yersinia species are globally distributed but are most prevalent in temperate and cold climates, ranking as
the third leading cause of bacterial diarrhea in Europe. Transmission is primarily through contaminated food, such as raw
pork or unpasteurized milk.
This study describes a protocol for isolating and identifying Yersinia strains from food samples, focusing on enrichment
and selective culture techniques followed by rapid identification using MALDI-TOF mass spectrometry. Enrichment in
ITC broth, recommended by ISO10273, and subsequent isolation on SSDC selective media enabled the recovery of
distinct Yersinia colonies. MALDI-TOF provided species-level identification based on protein spectral analysis, with a
scoring system ensuring accuracy.
Application of this protocol to fresh meat samples led to the isolation of Yersinia frederiksenii, a species previously
identified in various environmental and animal sources. This study highlights the utility of combined enrichment, selective
culturing, and MALDI-TOF for studying Yersinia in food microbiology and zoonotic disease research.
