Composition and evaluation of the efficacy of Staphylococcus aureus vaccine.

An alum-precipitated Staphylococcus aureus vaccine, composed of a formalin-inactivated whole culture of a strain which produces Smith surface antigen and combined with the whole culture of a highly toxigenic strain, was found to afford a good immunity to staphylococcal skin infection in rabbits. Three injections of the vaccine provided immunity which lasted for at least 6 months against a primarily pyogenic strain of S. aureus and for at least 3 months against a toxigenic strain. From experiments using vaccines prepared from cells or toxoid only, it was deduced that, although there is a measure of strain specific immunity, a good heterologous immunity can be established with a combined product provided that it contains adequate quantities of toxoid. The use of such a vaccine as a potential aid in the control of bovine staphylococcal mastitis is discussed.