title: Isolation and characterisation of Rhodococcus equi from submaxillary lymph nodes of wild boars (Sus scrofa).
abstract: Rhodococcus equi has been isolated from the submaxillary lymph nodes of domesticated pigs, but little is known about the presence of R. equi in wild boars. The aim of the study was the evaluation of the incidence of R. equi in wild boars and the characterisation of them. Of 482 submaxillary lymph nodes of wild boars shot in 39 settlements throughout Hungary, R. equi was isolated from 60 specimens, and plasmid types of 82 isolates were examined. The isolates were tested for the presence of 15-17-kDa (VapA) and 20-kDa virulence-associated protein antigen (VapB) genes by polymerase chain reaction (PCR). Plasmid DNAs were isolated and analysed by digestion with restriction endonucleases to estimate size and compare their polymorphisms. None of the 82 isolates contained vapA gene but 21 isolates (25.6%) were positive for vapB gene showing 827bp product of the expected size in the PCR amplification. Sixty-one strains (74.4%) did not contain plasmid. The 21 isolates of intermediate virulence contained virulence plasmids that were identified as types 1 (1 isolate), 5 (16 isolates), 21 (1 isolate), and three new distinct plasmid variants (1-1-1 isolate), respectively. On the basis of restriction digestion patterns of plasmid DNAs, we tentatively designated the new variants as types 25-27, respectively. The prevalence of R. equi strains of intermediate virulence among the isolates originated from the submaxillary lymph nodes of wild boars (25.6%) is very similar to those of domestic pigs (26.8%) in Hungary, and plasmid type 5 is the predominating one in both groups. This is the first report of isolation of VapB-positive R. equi from wild boars in the world.
authors.affiliation: Department of Microbiology and Infectious Diseases, Faculty of Veterinary Science, Szent István University, Hungária krt. 23-25, H-1143 Budapest, Hungary.
authors.forename: László
authors.initials: L
authors.lastname: Makrai
authors.forename: Ayumi
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Misa
authors.initials: M
authors.lastname: Matsuoka
authors.forename: Yukako
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kakuda
authors.forename: Béla
authors.initials: B
authors.lastname: Dénes
authors.forename: István
authors.initials: I
authors.lastname: Hajtós
authors.forename: István
authors.initials: I
authors.lastname: Révész
authors.forename: Katalin
authors.initials: K
authors.lastname: Jánosi
authors.forename: László
authors.initials: L
authors.lastname: Fodor
authors.forename: János
authors.initials: J
authors.lastname: Varga
authors.forename: Shinji
authors.initials: S
authors.lastname: Takai
mesh_terms: D000193:Actinomycetales Infections / Q000382:microbiology / Q000662:veterinary*; D000818:Animals; D008198:Lymph Nodes / Q000382:microbiology*; D016929:Rhodococcus equi / Q000302:isolation & purification*; D034421:Sus scrofa / Q000382:microbiology*; D013553:Swine Diseases / Q000382:microbiology