Enteropathogenic Yersinia with Public Health Relevance Found in Dogs and Cats in Finland

Yersiniosis is a common zoonotic enteral disease among humans, which has been linked to pigs and contaminated food, especially pork. Studies on yersiniosis in pets are very scarce. In this study, we performed pheno- and genotypic characterization of 50 Yersinia strains isolated from pets in Finland between 2012 and 2023. Y. enterocolitica 4/O:3/ST135, the most common type in human yersiniosis, was also the most common Y. enterocolitica type (68%) found in clinical faecal samples in our study. Also, human pathogenic Y. enterocolitica 2/O:9/ST139 and Y. pseudotuberculosis O:1/ST9 and O:1/ST42 strains carrying all essential pathogenic genes were identified. Three Y. enterocolitica 4/O:3/ST9 strains were multi-drug resistant and two of them were highly related showing one allelic difference (AD) with core-genome multi-locus sequence typing. Non-pathogenic, genotypically highly diverse Y. enterocolitica 1A strains, showing more than 1000 ADs and missing the essential virulence genes, were also recognized in dogs and cats. Our study demonstrates that pets can excrete human pathogenic Y. enterocolitica and Y. pseudotuberculosis in their faeces and may serve as an infection source for human yersiniosis, especially in families with small children in close contact with their pets.