A new antibody-based strategy for treating or preventing Staplylococcus aureus infections utilizes IgM antibodies specific for one or more Staphylococcus aureus capsular antigens. Examples of such antibodies include (i) a polyclonal IgM antibody composition that is isolated from pooled donor plasma and enriched for those IgMs that specifically bind Staphylococcus aureus capsular antigens or (ii) one or more IgM monoclonal antibodies that specifically bind Staphylococcus aureus capsular antigens.
