A growing body of evidence suggests that the addition of adjunctive aminoglycoside therapy not only is unnecessary for patients with uncomplicated right-sided native valve S aureus IE but may cause harm. For example, 1 study showed that a 2-week monotherapy regimen of intravenous cloxacillin was equivalent to cloxacillin plus gentamicin administered for 2 In 2006, the US Food and Drug Administration (FDA) approved the use of daptomycin (6 mg kg 1 ) for the treatment of S aureus bacteremia and right-sided S aureus IE.13 In a reg- istrational open-label, multinational, clinical trial for the treat- ment of S aureus bacteremia or right-sided IE comparing the efficacy of daptomycin monotherapy with therapy that included low-dose (1 mg/kg IV every 8 hours or adjusted on the basis of renal function) gentamicin for the first 4 days, patients did equally well in either treatment arm. In the predefined subgroup of those with MRSA bacteremia, daptomycin demonstrated a 44.4% success rate compared with 31.8% for standard therapy; this difference was not statistically significant (absolute differ- ence, 12.6%, 95% confidence interval, 7.4 to 32.6; P=0.28). Of note, in a post hoc analysis of this landmark clinical trial,149 the addition of even such low-dose, short-course gentamicin in 1 arm of the study was significantly associated with renal toxic- ity, which occurred early and often, and the clinical association between gentamicin dose and duration was minimal. Thus, current evidence suggests that either parenteral -lactam or daptomycin short-course therapy is adequate for the treatment of uncomplicated MSSA right-sided IE. In contrast, glycopeptide therapy for MRSA right-sided IE may require more prolonged treatment regimens. For both MSSA and MRSA infections, use of adjunctive gentamicin for the treatment of S aureus bacteremia or right-sided NVE is discouraged Recommendation 1. 