Free-living animals are an important environmental reservoir of pathogens dangerous for other animal species and humans. One of them is Yersinia (Y.) enterocolitica, a Gram-negative bacillus belonging to the Enterobacteriaceae family, the causative agent of yersiniosis – foodborne, enzootic disease, significant for public health. In Europe, yersiniosis is a notifiable zoonotic disease which must be reported to authorities and presented in the annual report of the European Food Safety Authority (EFSA). Y. enterocolitica has ranked third among the pathogens that most frequently cause gastrointestinal disorders in Europe, after Campylobacter spp. and Salmonella spp.
The purpose of the study was to identify bioserotypes and virulence markers of
Y. enterocolitica strains isolated from fallow deer (Dama dama) obtained during the 2018/2019 hunting season in Poland. The materials for the study consisted of 144 rectal swabs from 72 fallow deer. Four strains of Y. enterocolitica were isolated. All strains belonged to bioserotype 1A/NI. The presence of ystB gene, directly related to Y. enterocolitica pathogenicity was detected in all strains using triplex PCR, with three pairs of primers for the ail, ystA, and ystB genes, encoding respectively Ail (attachment invasion locus) protein, YstA (Yersinia stable toxin A) and YstB (Yersinia stable toxin B) enterotoxins.
The problem of Y. enterocolitica reservoirs in wild animals was recognized relatively early as well in Europe as in the rest of the world. Y. enterocolitica strains isolated from fallow deer had the amplicons of the ystB gene, coding for YstB enterotoxin, what suggests they can be potential source of Y. enterocolitica infection for humans.