Antibiotic Treatment for Infective Endocarditis Caused by Common Organismsa
| Organism | Drug (Dose, Duration) | Comments |
|---|---|---|
| Streptococci | ||
| Penicillin-susceptibleb streptococci, S. gallolyticus | • 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 | • Penicillin G (4 mU IV q4h) or ceftriaxone (2 g IV qd) for 4 weeks plus Gentamicind (3 mg/kg qd IV or IM, as a single dosee or divided into equal doses q8h for 2 weeks) | Penicillin alone at this dose for 6 weeks or with gentamicin during the initial 2 weeks is preferred for prosthetic valve endocarditis caused by streptococci with penicillin MICs of ≤0.1 µg/mL. |
| • Vancomycinc as noted above for 4 weeks | — | |
| Moderately penicillin-resistantg streptococci, nutritionally variant organisms, or Gemella species | • Penicillin G (4-5 mU IV q4h) or ceftriaxone (2 g IV qd) for 6 weeks plus Gentamicind (3 mg/kg qd IV or IM as a single dosee or divided into equal doses q8h for 6 weeks) | Preferred for prosthetic valve endocarditis caused by streptococci with penicillin MICs of >0.1 µg/mL |
| • Vancomycinc as noted above for 4 weeks | Regimen is preferred by some. | |
| Enterococcih | ||
| • 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 to penicillin) and for isolates resistant to penicillin/ampicillin. | |
| • Ampicillin (2 g IV q4h) plus ceftriaxone (2 g IV q12h), both for 6 weeks | Use for E. faecalis isolates with high-level resistance to gentamicin and streptomycin or for pts at high risk for aminoglycoside nephrotoxicity | |
| Staphylococci | ||
| MSSA infecting native valves (no foreign devices) | • Nafcillin, oxacillin, or flucloxacillin (2 g IV q4h for 4-6 weeks) | 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) | 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. | |
| MRSA infecting native valves (no foreign devices) | • Vancomycinc (15 mg/kg IV q8-12h for 4-6 weeks) | No role for routine use of rifampin. Consider alternative treatment (see text) for MRSA with vancomycin MIC >1.0 or persistent bacteremia during vancomycin therapy. |
| MSSA infecting prosthetic valves | • Nafcillin, oxacillin, or flucloxacillin (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 MRSA; if β-lactam allergy is of the minor nonimmediate type, cefazolin can be substituted for oxacillin/nafcillin. |
| MRSA 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 a single dose for 4 weeks) | Can use another third-generation cephalosporin at comparable dosage | |
| • Ampicillin/sulbactam (3 g IV q6h for 4 weeks) | — | |
| Coxiella burnetii | ||
| • Doxycycline (100 mg PO q12h) plus hydroxychloroquine (200 mg PO q8h), both for 18 (native valve) or 24 (prosthetic valve) months | Follow serology to monitor response during treatment (anti-phase I IgG and IgA decreased 4-fold and IgM anti-phase II negative) and thereafter for relapse. | |
| Bartonella spp. | ||
• Ceftriaxone (2 g IV q24h) or ampicillin (2 g IV q4h) or doxycycline (100 mg PO q12h) for 6 weeks plus Gentamicin (1 mg/kg IV q8h for 3 weeks) | If pt is highly allergic to β-lactams, use doxycycline. | |
aDoses are for adults with normal renal function. Doses of gentamicin, streptomycin, and vancomycin must be adjusted for reduced renal function. Ideal body weight is used to calculate doses of gentamicin and streptomycin per kilogram (men = 50 kg + 2.3 kg per inch over 5 feet; women = 45.5 kg + 2.3 kg per inch over 5 feet).
bMIC, ≤0.1 µg/mL.
cVancomycin dose is based on actual body weight. Adjust for trough level of 10-15 µg/mL for streptococcal and enterococcal infections and 15-20 µg/mL for staphylococcal infections.
dAminoglycosides should not be administered as single daily doses for enterococcal endocarditis and should be introduced as part of the initial treatment. Target peak and trough serum concentrations of divided-dose gentamicin 1 h after a 20- to 30-min infusion or IM injection are ~3.5 µg/mL and ≤1 µg/mL, respectively; target peak and trough serum concentrations of streptomycin (timing as with gentamicin) are 20-35 µg/mL and <10 µg/mL, respectively.
eNetilmicin (4 mg/kg qd, as a single dose) can be used in lieu of gentamicin.
fMIC, >0.1 µg/mL and <0.5 µg/mL.
gMIC, ≥0.5 µg/mL and <8 µg/mL.
hAntimicrobial susceptibility must be evaluated; see text.
iRifampin increases warfarin and dicumarol requirements for anticoagulation.
Abbreviations: MIC, minimal inhibitory concentration; MRSA, methicillin-resistant S. aureus; MSSA, methicillin-sensitive S. aureus.