Comparison of Multiple-Locus Variable-Number Tandem Repeat Analysis Profiles of Enteropathogenic Yersinia spp. Obtained from Humans, Domestic Pigs, Wild Boars, Rodents, Pork and Dog Food

SIMPLE SUMMARY: Yersiniosis in humans is a gastrointestinal disease sometimes complicated by more severe symptoms with long-lasting consequences, such as reactive arthritis and erythematous nodosum. The identification of the source of this infection can be difficult due to several reasons. The food items responsible for the spread of the infection can be difficult to identify or have been consumed. Also, the cultivation of the bacteria Yersinia (Y.) enterocolitica and Yersinia pseudotuberculosis is laborious and difficult. Even after successful cultivation, comparison between different strains of the bacteria is not straightforward, and available techniques depend on access to the bacteria in a pure culture. In the present study, possible reservoirs of these bacteria, such as wild boars and pork, were compared using multiple-locus variable-number tandem repeat analysis (MLVA), showing that wild boars can be a possible source of yersiniosis. This technique offers the possibility of identifying possible reservoirs of contaminated foodstuff without the need for cultivation of the bacteria. This study also shows the presence of Y. entercolitica in minced meat from wild boars. ABSTRACT: The enteropathogenic Yersinia genus is commonly detected in wildlife including wild boars. Difficulties in its cultivation may hamper subsequent epidemiological studies and outbreak investigations. Multiple-locus variable-number tandem repeat analysis (MLVA) of Yersinia (Y.) enterocolitica and Y. pseudotuberculosis has proven useful in source attribution and epidemiological studies but has hitherto relied on the analysis of isolates. In the present study, MLVA profiles generated from 254 isolates of Y. enterocolitica indicated similarities between human, pig and rodent isolates. Further, MLVA analyses of 13 Y. pseudotuberculosis pure-cultured isolates were compared to MLVA analyses performed directly on the 14 PCR-positive enrichment broths from which the isolates originated, which showed matching MLVA profiles. This indicates that MLVA analysis performed directly on enrichment broths could be a useful method for molecular epidemiological investigations. In addition, 10 out of 32 samples of wild boar minced meat obtained from private hunters and from approved wild-game-handling establishments were PCR-positive for the presence of Y. enterocolitica and may indicate a risk for public health.