Six weeks of therapy is reasonable for PVE caused by S pneumoniae (Class IIa; Level of Evidence C). 3. High-dose penicillin or a third-generation cepha- losporin is reasonable in patients with IE caused by penicillin-resistant S pneumoniae without men- ingitis; if meningitis is present, then high doses of Table 9. Therapy for Endocarditis Involving a Prosthetic Valve or Other Prosthetic Material Caused by VGS and Streptococcus gallolyticus (bovis) Regimen Dose* and Route Duration, wk Strength of Recommendation Comments Penicillin-susceptible strain Aqueous crystalline penicillin G sodium 24 million U/24 h IV either continuously or in 4 6 equally divided doses 6 Class IIa; Level of Evidence B Penicillin or ceftriaxone together with gentamicin has not demonstrated superior cure rates compared with monotherapy with penicillin or ceftriaxone for patients with highly susceptible strain; gentamicin therapy should not be administered to patients with creatinine clearance <30 mL/min. Or Ceftriaxone 2 g/24 h IV or IM in 1 dose 6 Class IIa; Level of Evidence B With or without Gentamicin sulfate 3 mg/kg per 24 h IV or IM in 1 dose 2 Ampicillin 2 g IV every 4 h is a reasonable alternative to penicillin if a penicillin shortage exists. Vancomycin hydrochloride 30 mg/kg per 24 h IV in 2 equally divided doses 6 Class IIa; Level of Evidence B Vancomycin is reasonable only for patients unable to tolerate penicillin or ceftriaxone. Penicillin relatively or fully resistant strain (MIC >0.12 g/mL) Aqueous crystalline penicillin sodium 24 million U/24 h IV either continuously or in 4 6 equally divided doses 6 Class IIa; Level of Evidence B Ampicillin 2 g IV every 4 h is a reasonable alternative to penicillin if a penicillin shortage exists. 