Abstract: A monoclonal antibody that counteracts Staphylococcus aureus by specifically binding to wild-type immunoglobulin-binding proteins (IGBP) of S. aureus comprising a cross-specific CDR binding site recognizing at least three of the IGBP domains selected from the group consisting of Protein A (SpA) domains and immunoglobulin-binding protein (Sbi) domains SpA-A, SpA-B, SpA-C, SpA-D, SpA-E, Sbi-I, and Sbi-II, wherein the antibody has an affinity to bind SpA-E with a KD of less than 5×10?9M as determined by a standard optical interferometry method for a F(ab)2 fragment, and preferably binds to wt SpA equally or better compared to mutant SpA-KKAA that lacks binding to IgG Fc or VH3.