Isolation of virulent Rhodococcus equi from native Japanese horses.
Abstract: R. equi was isolated from soil samples obtained from the environment of seven native Japanese horse breeds (Hokkaido, Kiso, Noma, Misaki, Tokara, Miyako and Yonaguni) and from fecal samples collected from three native horse breeds (Hokkaido, Kiso and Misaki). Virulent R. equi at various levels (ranging from 0.5 to 12.9%) was isolated from the feces or soil environment of Hokkaido, Kiso and Misaki horses. Isolates were investigated both for the presence of 15- to 17-kDa antigens (virulence-associated protein antigens; VapA) by colony blotting, using the monoclonal antibody 10G5, and the gene of VapA by PCR. Plasmid DNAs extracted from positive isolates were digested with restriction endonucleases, and the digestion patterns of the plasmids of virulent isolates were divided into three types. Two of the three types (87-kb type II and 90-kb type I) had already been reported in Japanese isolates, and a new type (tentatively designated as 90-kb type II) had been found in isolates from Kiso horses. Six virulent R. equi isolates from the Hokkaido horses contained an 87-kb type II plasmid. Eight of 24 isolates from the Kiso horses contained an 87-kb type II plasmid, and the remaining 16 contained a 90-kb type II (a new type) plasmid. Two isolates from the Misaki horses contained a 90-kb type I plasmid. These results demonstrate the geographic difference in the distribution of virulence plasmids in R. equi isolates among native Japanese horses.
Publication Date: 2001-03-15 PubMed ID: 11247045DOI: 10.1016/s0147-9571(00)00022-9Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The researchers isolated the bacterium Rhodococcus equi, particularly its virulent strains, from soil and fecal samples related to various native horse breeds in Japan. The presence of virulent R. equi varied in concentration in different breeds and environments. Plasmid DNA extracted from positive samples underwent analysis and revealed three distinct types of virulent isolates, with geographic variances in their distribution noticed among the native horses.
Methodology of the Research
- The researchers collected soil samples from the environment of seven native Japanese horse breeds and fecal samples from three breeds.
- These samples were analyzed to isolate Rhodococcus equi, particularly its virulent strains.
- The presence of 15- to 17-kDa virulence-associated protein antigens (VapA) was identified using colony blotting, a procedure involving the use of monoclonal antibody 10G5. VapA genes were also identified using polymerase chain reaction (PCR).
- Virulent R. equi was measured and found at various levels (ranging from 0.5 to 12.9%) in the feces or surrounding environment of three horse breeds.
Analysis of Plasmid DNA
- In positively identified samples, the researchers extracted plasmid DNA.
- These were digested with restriction endonucleases to describe their genetic composition.
- This analysis revealed three distinct types of virulent R. equi isolates: 87-kb type II, 90-kb type I, and a new, tentatively named 90-kb type II.
Geographical Variance Among Isolates
- These three types showed a geographical difference among the native horse breeds.
- The Hokkaido horses had six virulent R. equi isolates that contained an 87-kb type II plasmid.
- Among the 24 isolates from the Kiso horses, eight contained an 87-kb type II plasmid and the remaining 16 had a 90-kb type II plasmid (the newly identified type).
- Two isolates from Misaki horses contained a 90-kb type I plasmid.
Research Conclusions
- The researchers concluded that there is a distinct geographical variance in the distribution of virulence plasmids in R. equi isolates among native Japanese horses.
- The findings provide new insights into the diversity of R. equi isolates and how geography impacts the strains prevalent in horses.
Cite This Article
APA
Takai S, Ogawa K, Fukunaga N, Sasaki Y, Kakuda T, Tsubaki S, Anzai T.
(2001).
Isolation of virulent Rhodococcus equi from native Japanese horses.
Comp Immunol Microbiol Infect Dis, 24(2), 123-133.
https://doi.org/10.1016/s0147-9571(00)00022-9 Publication
Researcher Affiliations
- Department of Animal Hygiene, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori, Japan. takai@vmas.kitasato-u.ac.jp
MeSH Terms
- Actinomycetales Infections / epidemiology
- Actinomycetales Infections / microbiology
- Actinomycetales Infections / veterinary
- Animals
- Antibodies, Monoclonal
- DNA, Bacterial / isolation & purification
- Feces / microbiology
- Horse Diseases / epidemiology
- Horse Diseases / microbiology
- Horses
- Japan / epidemiology
- Plasmids
- Rhodococcus equi / genetics
- Rhodococcus equi / isolation & purification
- Rhodococcus equi / pathogenicity
- Soil Microbiology
- Virulence
Citations
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