가축 유래 staphylococcus aureus의 enterotoxin 산생과 plasmid profile에 관한 연구 V. R-plasmid의 분리 및 전이

Enterotoxin production and plasmid profiles of staphylococcus aureus isolated from domestic animals V. Isolation and transfer of staphylococcus aureus resistance plasmid

Animal source strains of Staphylococcus aureus were studies for the profiles of plasmids and the transfer of resistance plasmid by conjugation. A total of 50 isolates of S. aureus were subjected to the test for the presence of plasmid DNA. The isolates of bulk milk, chicken and Pig origin had 1 to 5 plasmid element. The plasmids recovered from these organisms had molecular weight ranging from 1.3 to 63 kb, 0.94 to 63 kb and 1.1 to 44 kb, respectively. In the strains isolated from bulk milk, the majority of the isolated plasmids was large molecular weight and they had one plasmid element. On the other hand, small molecular weight plasmids were predominant and they had multiple plasmid element in the isolates of chicken origin. Tetracycline and gentamicin resistant plasmid of S. aureus were transferable between S. aureus by filter mating method, but in the broth mating method were not transferable plasmids. The frequencies of tetracycline plasmid transfer between S. aureus strains were 2.0-5.2×10⁻⁷, and gentamicin plasmids transfer were 1.2×10⁻⁸.