title: Molecular typing of VapA-positive Rhodococcus equi isolates from Jeju native horses, Korea.
abstract: We recently demonstrated the presence of virulence-associated protein antigen (VapA)-positive Rhodococcus equi in Jeju Island, Korea. These bacteria contained one of two distinct plasmid types, a 90-kb type II plasmid, which has been found in isolates from the native Kiso horses of Japan, and a new variant, a 90-kb type V plasmid. However, the genotypic characters of the VapA-positive R. equi from Jeju native horses and their environments are poorly understood. Ninety-eight isolates from soil samples and 89 isolates from fecal samples were collected from five farms that breed or have bred Jeju native horses, and were tested for the presence of VapA by immunoblotting and PCR. Of the 98 soil isolates and 89 fecal isolates, seven and 13 were VapA-positive R. equi, respectively. In 2003, two Jeju foals died suddenly and were brought to the Faculty of Veterinary Medicine, Cheju National University, for postmortem examination. Pure cultures of R. equi were isolated from the lung lesions of both foals. Of the 16 clinical isolates, 14 were VapA-positive R. equi. Of the 34 VapA-positive clinical and environmental isolates, 16 contained the 90-kb type II plasmid and 18 contained a 90-kb type V plasmid. Pulsed-field gel electrophoresis (PFGE) patterns of the VapA-positive isolates from Jeju horses and Kiso horses, containing the 90-kb type II plasmid, were compared and formed two distinct groups. Furthermore, 18 virulent isolates containing the 90-kb type V plasmid formed two distinct PFGE groups (of 16 and two isolates). These results demonstrate that two virulence plasmid types are widespread in R. equi in Jeju native horses. However, there is little diversity in the PFGE patterns of virulent isolates, suggesting the clonal spread of virulent R. equi. The PFGE pattern of the virulent R. equi isolates from Jeju native horses in Korea is not identical to those of Kiso native horses in Japan.
authors.affiliation: Department of Veterinary Medicine, Cheju National University, Jeju 690-756, Korea.
authors.forename: Won-Geun
authors.initials: WG
authors.lastname: Son
authors.forename: Du-Sik
authors.initials: DS
authors.lastname: Lee
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamatoda
authors.forename: Fumiko
authors.initials: F
authors.lastname: Hatori
authors.forename: Nanako
authors.initials: N
authors.lastname: Shimizu
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kakuda
authors.forename: Yukako
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Shiro
authors.initials: S
authors.lastname: Tsubaki
authors.forename: Shinji
authors.initials: S
authors.lastname: Takai
mesh_terms: D000193:Actinomycetales Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D000818:Animals; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D005243:Feces / Q000382:microbiology; D014644:Genetic Variation; D006734:Horse Diseases / Q000453:epidemiology / Q000382:microbiology*; D006736:Horses; D015151:Immunoblotting / Q000662:veterinary; D007723:Korea / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D016929:Rhodococcus equi / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity*; D012988:Soil Microbiology; D037521:Virulence Factors / Q000235:genetics / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D037521:Virulence Factors