The high prevalence of methicillin resistance among Staphylococcus aureus bacteremias leads to common use of vancomycin as empirical therapy. However, investigators have reported poor outcomes with vancomycin treatment for methicillin-susceptible Staphylococcus aureus bacteremia. We review the evidence supporting empirical combination of both vancomycin and a β-lactam agent for Staphylococcus aureus bacteremia. Vancomycin therapy for methicillin-susceptible Staphylococcus aureus bacteremia is associated with 2-3 times the risk of morbidity and mortality compared to an antistaphylococcal penicillin (oxacillin and nafcillin) or first-generation cephalosporin (cefazolin). De-escalation of empirical vancomycin to definitive β-lactam therapy still appears inferior to initial β-lactam therapy. Although there is no clinical trial supporting combination therapy, a scientific rationale for benefit exists and should be weighed against the risks (adverse events, antibiotic resistance, and cost) of additional pharmacotherapy. The empirical combination of vancomycin and a β-lactam (either nafcillin, oxacillin, or cefazolin) for staphylococcal bacteremia may improve infection-related clinical outcomes.
Keywords: MRSA; MSSA; empirical therapy; nafcillin; vancomycin.