Monoclonal antibodies which can bind to the Fnbp protein of Staphylococcus aureus and which are generated from a peptide from the D2 region of fibronectin binding protein B (Fnbp) of S. aureus are provided which can be useful in the treatment and protection against infection from staphylococcal bacteria such as Staphylococcus aureus. The monoclonal antibodies of the invention are advantageous in that they bind S. aureus in high affinity and thus can be useful in the prevention of the adherence of staph bacteria to host cells by impairing or inhibiting the ability of S. aureus Fnbp to bind to fibronectin. Kits and methods of utilizing the monoclonal antibodies of the invention are also provided.