title: Molecular typing of Streptococcus suis isolates from Iberian pigs: a comparison with isolates from common intensively-reared commercial pig breeds.
abstract: The Iberian pig (IP) is a traditional Spanish breed variety of the domestic pig (Sus scrofa domesticus) with high economic importance because of the value of the dry-cured products in national and international markets. The genetic characteristics of tonsillar and clinical Streptococcus suis isolates from the IP maintained under extensive or intensive management conditions were investigated. S. suis isolates from IP pigs were compared with S. suis isolates from intensively-farmed pigs of common breeds (CBP). S. suis was isolated from 48.4% of the IP tonsils examined, indicating wide distribution among IP pigs. Serotypes 1 (9.4%), 2 (8.6%) and 9 (7%) were the most commonly found, although a high percentage of S. suis isolates were not typeable by coagglutination testing. No significant differences in carrier rates or serotype diversity were observed between management systems, indicating that intensive farming does not influence S. suis colonisation. Both pulsed-field gel electrophoresis and multiple-locus variable number tandem repeat analysis showed a serotype-based distribution of S. suis IP isolates. Serotypes 1 and 2 S. suis isolates were grouped in the same cluster, whereas isolates of serotypes 9 and 7 were assigned to another cluster. All clinical and most tonsillar serotype 2 IP isolates were assigned to sequence type 1 (ST1) and exhibited the virulence genotype mrp+/epf+/sly+, indicating a high distribution of this genetic lineage among IP as well as a population of serotype 2 common to IPs and CBPs. The only clinical isolate of serotype 9 from IP was assigned to ST123, a sequence type associated with clinical isolates in CBPs in Spain.
authors.affiliation: Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Sánchez Del Rey
authors.affiliation: Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain; Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: J F
authors.initials: JF
authors.lastname: Fernández-Garayzábal
authors.affiliation: Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Bárcena
authors.affiliation: Centro de Investigación en Sanidad Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ministerio de Economia y Competitividad, Valdeolmos, 28130 Madrid, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Briones
authors.affiliation: Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Domínguez
authors.affiliation: Groupe de Recherche sur les Maladies Infectieuses du Porc, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, St.-Hyacinthe, Québec J2S 2M2, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Gottschalk
authors.affiliation: Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain; Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain. Electronic address: avela@vet.ucm.es.
authors.forename: A I
authors.initials: AI
authors.lastname: Vela
mesh_terms: D000818:Animals; D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D014644:Genetic Variation; D008969:Molecular Sequence Data; D060885:Multiplex Polymerase Chain Reaction / Q000662:veterinary; D014066:Palatine Tonsil / Q000382:microbiology; D010802:Phylogeny; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D017422:Sequence Analysis, DNA / Q000662:veterinary; D065288:Serogroup; D013030:Spain / Q000453:epidemiology; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D017011:Streptococcus suis / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000382:microbiology*; D020080:Tandem Repeat Sequences; D014774:Virulence
keywords: Iberian pigs; Molecular characterisation; Streptococcus suis