Ceftobiprole medocaril is a cephalosporin antibiotic with anti-MRSA (Methicillin-Resistant Staphylococcus aureus) activity. Ceftobiprole medocaril in not approved for the treatment of bacterial blood stream infections. S. aureus is a major human pathogen. It causes a wide range of serious infections, including skin and skin structure infections, infections of vascular devices and catheters, and infections of the heart and lungs, bones and joints, and deep tissues. Particularly challenging and difficult to treat are blood-borne infections (bacteremia). Bacteremic infections are prone to relapse and they are often complicated by metastatic seeding of sites throughout the body. MRSA strains are increasing in prevalence, incidence, and virulence. Moreover, the frequency of patients presenting with persistent MRSA bacteremia appears to be rising. The objective of the open label trial is to compare the effectiveness and safety of ceftobiprole versus a comparator in patients with MRSA and MSSA (methicillin-susceptible Staphylococcus aureus) in bacteremic patients. Patients who meet inclusion and exclusion criteria and consent to participate in the study will be randomly assigned to either ceftobiprole or comparator. The primary end point is time to bloodstream clearance of MRSA and MSSA in patients. Patients will be randomized to either ceftobiprole or comparator for 7 days.