Two part clinical trial designed to evaluate the efficacy of StaphVAX in adults on hemodialysis. Part A will evaluate the prevention of bacteremic infections in End Stage Renal Disease (ESRD) patients during the interval between 3 and 35 weeks after a single dose of StaphVAX. Part B of this study is designed to assess immunogenicity of a second [booster] dose of vaccine in patients completing Part A, and the cumulative (Part A + B) efficacy.