젖소 유방염유래 Staphylococcus aureus에서 용원변환에 의한 staphylokinase 산생

Staphylokinase is seldom formed by animal Staphylococcus aureus strains. In this study, 76(72.4%) of 105 Staph aureus strains isolated from bovine mastitis were found to produce a staphylokinase. These staphylokinase producing strains were tested for lysogenic conversion by means of delysogenization procedure and isolation of serotype B and F converting phages. By the application of delysogenization method comprised of UV irradiation and acriflavine treatment to 76 staphylokinase-positive strains, the delysogenized cells could be observed in 29(38.2%) of the strains and delysogenization rates in 16(55.2%) of 29 delysogenized strains were 0.9% or less. A total of 7 serological group F phages were isolated from 76 staphylokinase-positive strains, and these phages could be again divided into three groups by the immunity reaction. Of 7 serotype F phages, 2 were isolated from the original lysogenic strains producing colonies of delysogenized cells after delysogenizing treatments and 5 were isolated from strains in which delysogenized cells were not observed after delysogenizing treatments. Difference of sensitivities to serological group F phages between original lysogenic strains and strains from which delysogenized cells were not isolated after delysogenizing treatments was not observed These data suggest that staphylokinase production of the remaining 42 strains might be also mediated by lysogenic conversion.