Staphylococcus aureus was treated with antagonistic bacterium X23 fermentation liquid,then the number of bacterial colonies was counted using agar plate pouring method,and the morphology and ultrastructure of the bacteria were observed using scanning electron-microscope（SEM） and transmission electron-microscope（TEM） respectively to study the bactericidal effect and partial mechanism of antagonistic bacterium X23 fermentation liquid on S.aureus.The result showed that the number of S.aureus colonies in the treated groups was significantly low...
