Baltimore et al Infective Endocarditis in Childhood: 2015 Update 1499 Table 7. Recommended Antibiotic Treatments for Pediatric Infective Endocarditis* Organism/Condition Recommended Antibiotic Drug/Daily Antibiotic Dose Alternative Antibiotic Drug Choice Unknown agent (initial empirical therapy or culture-negative endocarditis, generally after at least 48 h of attempting to culture the causative organism except in severely ill children) Native valve (community acquired) or late prosthetic valve (>1 y after surgery) infection Ampicillin/sulbactam plus gentamicin Vancomycin (plus gentamicin) With or without vancomycin For prosthetic valve endocarditis, add rifampin IV divided every 4 6 h up to 12 g daily IV divided every 6 h up to 2 g IV divided every 8 h. IV divided every 8 divided every 12 h up to 600 mg IV every 6 h up to 2 g Nosocomial endocarditis associated with vascular cannulae or early prosthetic valve endocarditis ( 1 y after surgery) Vancomycin plus gentamicin ( rifampin if prosthetic material present) ? 