Organism

Drug, Dose, Duration

Comments

Streptococci

Penicillin-susceptibleb streptococci, S. bovis

Penicillin G (2-3 mU IV q4h for 4 weeks)

—

Ceftriaxone (2 g/d IV as a single dose for 4 weeks)

Can use ceftriaxone in pts with nonimmediate penicillin allergy

Vancomycinc (15 mg/kg IV q12h for 4 weeks)

Use vancomycin in pts with severe or immediate β-lactam allergy

Penicillin G (2-3 mU IV q4h) or ceftriaxone (2 g IV qd) for 2 weeks

plus gentamicind (3 mg/kg qd IV or IM as a single dosee or divided into equal doses q8h for 2 weeks)

Avoid 2-week regimen when risk of aminoglycoside toxicity is increased and in prosthetic valve or complicated endocarditis

Relatively penicillin-resistantf streptococci

Penicillin G (4 mU IV q4h) or ceftriaxone (2 g IV qd) for 4 weeks

plus gentamicin^d (3 mg/kg qd IV or IM as a single dose^e or divided into equal doses q8h for 2 weeks)

Vancomycin^c as noted above for 4 weeks

Penicillin alone at this dose for 6 weeks or with gentamicin during initial 2 weeks preferred for prosthetic valve endocarditis caused by streptococci with penicillin MICs of ≤0.1 μg/mL

Moderately penicillin-resistantg streptococci, nutritionally variant organisms, or Gemella morbillorum

Penicillin G (4-5 mU IV q4h) or ceftriaxone (2 g IV qd) for 6 weeks

plus gentamicin^d (3 mg/kg qd IV or IM as a single dose^e or divided into equal doses q8h for 6 weeks)
Vancomycin^c as noted above for 4 weeks

Preferred for prosthetic valve endocarditis caused by streptococci with penicillin MICs of >0.1 μg/mL

Enterococci^h

Penicillin G (4-5 mU IV q4h) plus gentamicind (1 mg/kg IV q8h), both for 4-6 weeks

Can use streptomycin (7.5 mg/kg q12h) in lieu of gentamicin if there is not high-level resistance to streptomycin

Ampicillin (2 g IV q4h) plus gentamicind (1 mg/kg IV q8h), both for 4-6 weeks

—

Vancomycinc (15 mg/kg IV q12h) plus gentamicind (1 mg/kg IV q8h), both for 4-6 weeks

Use vancomycin plus gentamicin for penicillin-allergic pts, or desensitize these pts to penicillin

Staphylococci

Methicillin-susceptible, infecting native valves (no foreign devices)

Nafcillin or oxacillin (2 g IV q4h for 4-6 weeks) plus (optional) gentamicind (1 mg/kg IM or IV q8h for 3-5 days)

Can use penicillin (4 mU q4h) if isolate is penicillin-susceptible (does not produce β-lactamase)

Cefazolin (2 g IV q8h for 4-6 weeks) plus (optional) gentamicind (1 mg/kg IM or IV q8h for 3-5 days)

Can use cefazolin regimen for pts with nonimmediate penicillin allergy

Vancomycinc (15 mg/kg IV q12h for 4-6 weeks)

Use vancomycin for pts with immediate (urticarial) or severe penicillin allergy

Methicillin-resistant, infecting native valves (no foreign devices)

Vancomycinc (15 mg/kg IV q12h for 4-6 weeks)

No role for routine use of rifampin

Methicillin-susceptible, infecting prosthetic valves

Nafcillin or oxacillin (2 g IV q4h for 6-8 weeks) plus gentamicind (1 mg/kg IM or IV q8h for 2 weeks) plus rifampini (300 mg PO q8h for 6-8 weeks)

Use gentamicin during initial 2 weeks; determine susceptibility to gentamicin before initiating rifampin; if pt is highly allergic to penicillin, use regimen for methicillin-resistant staphylococci; if β-lactam allergy is of the minor, nonimmediate type, can substitute cefazolin for oxacillin/nafcillin

Methicillin-resistant, infecting prosthetic valves

Vancomycinc (15 mg/kg IV q12h for 6-8 weeks) plus gentamicind (1 mg/kg IM or IV q8h for 2 weeks) plus rifampinⁱ (300 mg PO q8h for 6-8 weeks)

Use gentamicin during initial 2 weeks; determine gentamicin susceptibility before initiating rifampin

HACEK organisms

Ceftriaxone (2 g/d IV as single dose for 4 weeks)

Can use another third-generation cephalosporin at comparable dosage

Ampicillin/sulbactam (3 g IV q6h for 4 weeks)

—