Prospective, multicenter study of Staphylacoccus aureus bacteremia. Risk factors for endocarditis and methicillin-resistance

222 patients with community-acquired S. aureus bacteremia were followed prospectively for 6 months from onset of bacteremia. The most common portal was wound/skin (25%). 6% of patients had no underlying disease or risk factors. Complications included abscesses (10%), osteomyelitis (8%), septic arthritis (4%), meningitis (4%), septic thrombosis (3%). 19% (42/222) were ultimately found to have endocarditis. IV drug use and heart disease were risk factors for endocarditis (p < 0.001). 24% of endocarditis had insulin dependent diabetes vs. 12% of the nonendocarditis patients (p = 0.08). At 60 days, mortality was 31% for endocarditis patients vs. 18% for nonendocarditis patients (p = 0.08). 24% (53/222) had methicillin-resistant S. aureus (MRSA) including 9 with MRSA endocarditis. Risk factors for MRSA included skin disease and chronic illnesses. Surprisingly, mortality was not different between MRSA vs. MSSA patients including those with endocarditis. Patients with MSSA bacteremia treated with nafcillin had no (0%) recurrences compared to a 14% recurrence rate for vancomycin.