A composition containing wall teichoic acid-attached peptidoglycan (WTA-PGN) as an active ingredient, a method for preventing or treating Staphylococcus aureus infectious diseases using the composition, and a method for preparing a soluble WTA-PGN which can be used as an active ingredient in the composition are provided. The composition of the present invention can be effectively used for preventing or treating Staphylococcus aureus infectious diseases by opsonophagocytosis due to antigen-antibody reaction and neutrophil-mediated phagocytosis due to T cell activation at the early stage of infection.
