Disclosed herein are monoclonal antibodies or binding portion thereof that bind specifically to a Staphylococcus spp. autolysin N-acetylmuramoyl-L-alanine amidase catalytic domain and / or cell wall binding domain, as well as pharmaceutical compositions containing the same. Cell lines expressing the monoclonal antibodies, including hybridomas, are also disclosed. Methods of using the monoclonal antibodies for installation of orthopedic implants, grafts or medical devices, treating or preventing a Staphylococcus infection, and treating osteomyelitis are described, as are diagnostic methods for the detection of Staphylococcus in a sample.