title: Variation in the prevalence of enteropathogenic Yersinia in slaughter pigs from Belgium, Italy, and Spain.
abstract: Tonsils of 829 fattening pigs originating from Belgium (n = 201), Italy (n = 428), and Spain (n = 200) were collected between 2005 and 2007 to study the prevalence of enteropathogenic Yersinia in slaughter pigs. Isolation of Yersinia enterocolitica and Yersinia pseudotuberculosis was done by selective enrichment and by cold enrichment for 7 and 14 days. Pathogenic Y. enterocolitica and Y. pseudotuberculosis isolates were identified by polymerase chain reaction targeting the chromosomal genes ail and inv, respectively, as well as the plasmid-encoded virF of both species. A significantly higher (p < 0.001) prevalence of ail-positive Y. enterocolitica in Spain (93%) than in Belgium (44%) or Italy (32%) was observed. virF-positive Y. enterocolitica was present in 77% of ail-positive samples. Bioserotype 4/O:3 was the most common type in all three countries. Bioserotypes 2/O:5 and 3/O:9 were found in Italy (1%) and Belgium (9%), respectively. The prevalence of inv- and virF-positive Y. pseudotuberculosis was 2% and 1% in Belgium and Italy, respectively. Y. pseudotuberculosis was not detected in pigs from Spain. Bioserotypes 1/O:1 (20%), 1/O:2 (20%), and 2/O:3 (60%) were found in Belgium, and 1/O:1 (60%) and 2/O:3 (20%) in Italy. The most efficient method for isolation of Y. enterocolitica was combined cold enrichment for 7 and 14 days; however, the isolation method for Y. pseudotuberculosis was cold enrichment for 14 days. Fattening pigs seem to be an important reservoir of pathogenic Y. enterocolitica in Belgium, Italy, and Spain. Bioserotype 4/O:3 of Y. enterocolitica and bioserotypes 2/O:3 and 1/O:1 of Y. pseudotuberculosis have been shown to predominate.
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland. pilar.ortiz@helsinki.fi
authors.forename: Pilar Ortiz
authors.initials: PO
authors.lastname: Martínez
authors.forename: Maria
authors.initials: M
authors.lastname: Fredriksson-Ahomaa
authors.forename: Adolfo
authors.initials: A
authors.lastname: Pallotti
authors.forename: Roberto
authors.initials: R
authors.lastname: Rosmini
authors.forename: Kurt
authors.initials: K
authors.lastname: Houf
authors.forename: Hannu
authors.initials: H
authors.lastname: Korkeala
mesh_terms: D000818:Animals; D001530:Belgium / Q000453:epidemiology; D003080:Cold Temperature; D004197:Disease Reservoirs / Q000662:veterinary*; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008460:Meat / Q000382:microbiology; D014066:Palatine Tonsil / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D015995:Prevalence; D012703:Serotyping / Q000379:methods / Q000662:veterinary; D013030:Spain / Q000453:epidemiology; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000382:microbiology*; D013997:Time Factors; D015009:Yersinia Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D015008:Yersinia enterocolitica / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D015011:Yersinia pseudotuberculosis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification