Endocarditis antimicrobial treatment


 * Associate Editors-in-Chief:

Overview
Effective treatment requires identification of the etiologic agent and determination of its antimicrobial susceptibility.

Timing of Initiation of Antibiotics
Antibiotic therapy for subacute or indolent disease can be delayed until results of blood cultures are known; in fulminant infection or valvular dysfunction requiring urgent surgical intervention, begin empirical antibiotic therapy promptly after blood cultures have been obtained.

Duration of Antibiotic Therapy
The duration for native valve endocarditis is often 4 weeks. For prosthetic valve endocarditis, treatment should be continued for 6 to 8 weeks. For each infective agent, the preferred antimicrobial agent, dose, and duration is listed below.

==Treatment Based Upon Infectious Agent ==

Preferred regimens

 * Penicillin G: If Minimum inhibitory concentration [MIC] <0.2 µg/ml. Dose is 12–18 million units I.V. daily in divided doses q. 4 hour for 4 weeks.


 * Penicillin G + gentamicin or ceftriaxone: Dose is penicillin G, 12–18 million units I.V. daily in divided doses q. 4 hour for 4 weeks; gentamicin, 3 mg/kg I.M. or I.V. daily in divided doses q. 8 hour for 2 weeks (peak serum concentration should be ~ 3 µg/ml and trough concentrations < 1 µg/ml); ceftriaxone, 2 g I.V. daily as a single dose for 2 weeks.


 * Vancomycin: for patients with history of penicillin hypersensitivity.Doseis 30 mg/kg I.V. daily in divided doses q. 12 hour for 4 weeks.

Preferred regimens

 * If MIC 0.2–0.5 µg/ml


 * Penicillin G + gentamicin: Dose is penicillin G, 20–30 million units I.V. daily in divided doses q. 4 hour for 4 weeks; gentamicin, 3 mg/kg I.M. or I.V. daily in divided doses q. 8 hr for 2 wk (peak serum concentration should be ~ 3 µg/ml and trough concentrations < 1 µg/ml).


 * If MIC > 0.5 µg/ml


 * Penicillin G + gentamicin: Dose is penicillin G, 20–30 million units I.V. daily in divided doses q. 4 hour for 4 week; gentamicin, 3 mg/kg I.M. or I.V. daily in divided doses q. 8 hour for 4 week (peak serum concentration should be ~ 3 µg/ml and trough concentrations < 1 µg/ml).


 * Vancomycin: regimen for patients with history of penicillin hypersensitivity. Dose is 30 mg/kg I.V. daily in divided doses q. 12 hour for 4 weeks.

Preferred regimens

 * Penicillin G + gentamicin:Dose is penicillin G, 20–30 million units I.V. daily in divided doses q. 4 hr for 4–6 weeks; gentamicin, 3 mg/kg I.M. or I.V. daily in divided doses q. 8 hour for 4–6 weeks (peak serum concentration should be ~ 3 µg/ml and trough concentrations < 1 µg/ml).


 * Ampicillin + gentamicin:Dose is ampicillin, 12 g I.V. daily in divided doses q. 4 hour for 4–6 weeks; gentamicin, dose as above.


 * Vancomycin + gentamicin: regimen for patients with history of penicillin hypersensitivity. Dose is vancomycin, 30 mg/kg I.V. daily in divided doses q. 12 hour for 4–6 weeks; gentamicin, dose as above.

Preferred regimens

 * Nafcillin or oxacillin + gentamicin (optional): Dose is nafcillin or oxacillin, 12 g I.V. daily in divided doses q. 4 hour for 4–6 weeks; gentamicin, 3 mg/kg I.M. or I.V. daily in divided doses q. 8 hr for 3–5 days (peak serum concentration should be ~ 3 µg/ml and trough concentrations <1 µg/ml).


 * Cefazolin + gentamicin (optional): alternative regimen for patients with history of penicillin hypersensitivity. Dose is cefazolin, 12 g I.V. daily in divided doses q. 4 hour for 4–6 weeks; gentamicin, dose as above.


 * Vancomycin: alternative regimen for patients with history of penicillin hypersensitivity. Dose is 30 mg/kg I.V. daily in divided doses q. 12 hr for 4–6 weeks.

Preferred regimens

 * Vancomycin: Doseis 30 mg/kg I.V. daily in divided doses q. 12 hour for 4–6 weeks.

Preferred regimens

 * Nafcillin or oxacillin + rifampin + gentamicin. Dose is nafcillin or oxacillin, 12 g I.V. daily in divided doses q. 4 hour for 6–8 weeks; rifampin, 300 mg p.o., q. 8 hour for 6–8 weeks; gentamicin (administer during the initial 2 weeks), 3 mg/kg I.M. or I.V. daily in divided doses q. 8 hour for 2 weeks.

Preferred regimens

 * Vancomycin + rifampin + gentamicin. Dose is vancomycin, 30 mg/kg I.V. daily in divided doses q. 12 hour for 6–8 weeks; rifampin, 300 mg p.o., q. 8 hour for 6–8 weeks; gentamicin (administer during the initial 2 weeks), 3 mg/kg I.M. or I.V. daily in divided doses q. 8 hour for 2 weeks.

HACEK Organisms

 * Ceftriaxone or another third-generation cephalosporin. Dose is 2 g I.V. daily as a single dose for 4 weeks.