Analysis of Yersinia pseudotuberculosis isolates recovered from deceased mammals of a German zoo animal collection.

Yersinia (Y.) pseudotuberculosis is an important pathogen for both humans and animals. It can infect livestock as well as pets and wild animals. During the last years, a number of reports describe the isolation of Y. pseudotuberculosis from zoo animals, mainly birds and mammals, for which the infection was mostly lethal. Between 2005 and 2019, there were at least 17 cases of deceased mammals belonging to five different species at the Zoo Wuppertal, Germany, which suffered from a Y. pseudotuberculosis infection. Since only scarce information exists on properties of Y. pseudotuberculosis from zoo animals, we characterized eight isolates, covering all infected species, in detail. All of them are members of biotype 1, but belong to five serotypes, five sequence types (STs) and even seven cgMLST types. Using Pulsed-Field Gel Electrophoresis (PFGE) analysis and whole-genome sequencing (WGS), seven isolates could be discriminated from each other. They differ significantly regarding their virulence genes and mobile genetic elements. While the virulence plasmid pYV existed in all serotypes (five isolates), a complete high pathogenicity island (HPI) was detected only in the serotypes O:1a, O:1b and O:13 (four isolates), but not in O:2a and O:2b. Similarly, the content of other plasmids and prophages varies greatly between the isolates. The data demonstrates that the deceased mammals were infected by seven individual isolates and not by a single type predominating in the zoo animals.