MOLECULAR EPIDEMIOLOGY OF ANIMAL-PATHOGENIC STAPHYLOCOCCI,USING PULSED-FIELD GEL ELECTROPHORESIS

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Staphylococcus hyicus and Staphylococcus intermedius have been implicated in a variety of infections in animals, however, both of them are also distributed in healthy animals. For the epidemiologic study of these organisms, an appropriate marker is needed for differentiating virulent and avirulent strains. For that purpose, we investigated whether or not genomic DNA fingerprinting, using pulsed-fiels gel electrophoresis (PFGE), is applicable. First, appropriate conditions of PFGE method was determined, and applied to the analysis of S.hyicus strains from various animals species. Specific banding patterns were observed according to the animal species, suggesting that ecovars based on the genetic background may be present in S.hyicus. Regarding S.hyicus infections in animals, that in pigs is the most serious problem. Most (90%) of strains from diseased pigs showed a specific combination of bands, while strains from healthy ones showed a variety of banding patterns, suggesting that PFGE a … More nalysis may enable us to distinguish virulent strains of S.hyicus. On the other hand, the virulent banding patten was also detected in some strains from healthy pigs. This may suggest that not only in the side of organism but in the side of animal host factors for manifesting disease are present. Exoproteins of S.hyicus strains was analyzed by SDS-PAGE.Virulent strains of S.hyicus revealed an extensive amount of a specific protein, while avirulent ones did remarkablly less amount of the protein or not.With regard to S.intermedius, it showed a high degree of banding patterns in PFGE analysis, suggesting that the pathogenicity could not be assessed by the test. It was proved that strains of this organism are heterogeneous.A mouse model was applied to the analysis of the two species of Staphylococcus. It could not reveal the virulence of strains, suggesting that host factors may be important in pathogenesis of those diseases.We conclude that PFGE analysis is a powerful tool for epidemiologic or ecologic studies of S.hyicus and S.intermedius. Less