Other less active (in vitro) combinations with daptomycin include gentamicin, rifampin, or tigecycline. Table 14. Vancomycin-Containing Regimens for Vancomycin- and Aminoglycoside-Susceptible Penicillin-Resistant Enterococcus Species for Native or Prosthetic Valve (or Other Prosthetic Material) IE in Patients Unable to Tolerate -Lactam Regimen Dose* and Route Duration, wk Strength of Recommendation Comments Unable to tolerate -lactams Vancomycin 30 mg/kg per 24 h IV in 2 equally divided doses 6 Class IIa; Level of Evidence B Plus Gentamicin 3 mg/kg per 24 h IV or IM in 3 equally divided doses Penicillin resistance; intrinsic or -lactamase producer Vancomycin 30 mg/kg per 24 h IV in 2 equally divided doses 6 Class IIb; Level of Evidence C For -lactamase producing strain, if able to tolerate a -lactam antibiotic, ampicillin-sulbactam plus aminoglycoside therapy may be used. Plus Gentamicin 3 mg/kg per 24 h IV or IM in 3 equally divided doses IE indicates infective endocarditis; IM, intramuscular; and IV, intravenous. *Doses recommended are for adults with normal renal function. Dose of vancomycin should be adjusted to obtain a serum trough concentration of 10 to 20 g/mL. Dose of gentamicin should be adjusted to obtain serum peak and trough concentrations of 3 to 4 and <1 g/mL, respectively. Ampicillin-sulbactam dosing is 3 g/6 hour IV. Baddour et al Infective Endocarditis in Adults 1461 Recommendations 1. Patients with IE attributable to Enterococcus spe- cies resistant to penicillin, aminoglycosides, and vancomycin should be managed by specialists in infectious diseases, cardiology, cardiovascular sur- gery, clinical pharmacy, and, if necessary, pediatrics (Class I; Level of Evidence C). 2. If daptomycin therapy is selected, then doses of 10 may be considered (Class IIb; Level of Evidence C). 3. 