ABSTRACTYersiniosis is strongly associated with the consumption of pork contaminated with enteropathogenicYersinia enterocolitica, which is harbored by domestic pigs without showing clinical signs of disease. In contrast to data onY. enterocoliticaisolated from conventionally reared swine, investigations into the occurrence ofY. enterocoliticain wild boars in Germany are rare. The objectives of the study were to get knowledge about these bacteria and their occurrence in wild boars hunted in northern Germany by isolation of the bacteria from the tonsils, identification of the bioserotypes, determination of selected virulence factors, macrorestriction analysis, multilocus sequence typing (MLST), and testing of antimicrobial susceptibility. Altogether, tonsils from 17.1% of 111 tested wild boars were positive forY. enterocoliticaby culture methods. All but two isolates belonged to biotype (BT) 1A, with the majority of isolates bearing aystBnucleotide sequence which was revealed to have 85% identity to internal regions ofY. enterocoliticaheat-stable enterotoxin type B genes. The remainingY. enterocoliticaisolates were identified to be BT 1B and did not carry the virulence plasmid. However, two BT 1A isolates carried theailgene. Macrorestriction analysis and results from MLST showed a high degree of genetic diversity of the isolates, although the region where the samples were taken was restricted to Lower Saxony, Germany, and wild boars were shot during one hunting season. In conclusion, mostY. enterocoliticaisolates from wild boars investigated in this study belonged to biotype 1A. EnteropathogenicY. enterocoliticabioserotypes 4/O:3 and 2/O:9, usually harbored by commercially raised pigs in Europe, could not be identified.
Nutritional requirements for synthesis of heat-stable enterotoxin by Yersinia enterocolitica.
