What is the first line empirical treatment for infective endocarditis?

From the Guidelines

The first-line empirical treatment for infective endocarditis typically consists of vancomycin (30-60 mg/kg/day i.v. in 2-3 doses) plus gentamicin (3 mg/kg/day i.v. or i.m. in 1 dose) while awaiting blood culture results, as recommended by the 2015 ESC guidelines 1. This combination provides broad coverage against the most common causative organisms, including Staphylococcus aureus (including MRSA), viridans group streptococci, and enterococci.

• For patients with native valve endocarditis, ampicillin (12 g/day i.v. in 4-6 doses) or (flu)cloxacillin or oxacillin (12 g/day i.v. in 4-6 doses) may be used as an alternative, as suggested by the 2015 ESC guidelines 1.
• For patients with early prosthetic valve endocarditis (<12 months post surgery) or nosocomial and non-nosocomial healthcare-associated endocarditis, vancomycin (30 mg/kg/day i.v. in 2 doses) plus gentamicin (3 mg/kg/day i.v. or i.m. in 1 dose) is recommended, with the addition of rifampin (900-1200 mg i.v. or orally in 2 or 3 divided doses) in certain situations, as recommended by the 2015 ESC guidelines 1. Treatment duration is typically 4-6 weeks, depending on the pathogen identified, valve involvement (native vs. prosthetic), and presence of complications.
• Dosing adjustments are necessary for patients with renal impairment, as emphasized by the 2015 AHA statement 1.
• Blood cultures should be obtained before initiating antibiotics whenever possible, and therapy should be narrowed once the causative organism and susceptibilities are identified, as recommended by the 2015 AHA statement 1.
• Surgical intervention may be necessary in cases with valve dysfunction, persistent infection, or embolic complications, as suggested by the 2005 AHA statement 1. Close monitoring of clinical response, inflammatory markers, and potential antibiotic toxicity is essential throughout the treatment course, as emphasized by the 2015 ESC guidelines 1 and the 2015 AHA statement 1.

From the FDA Drug Label

Vancomycin Hydrochloride for Injection, USP is effective in the treatment of staphylococcal endocarditis Vancomycin Hydrochloride for Injection, USP has been reported to be effective alone or in combination with an aminoglycoside for endocarditis caused by S. viridans or S. bovis.

The first line empirical treatment for infective endocarditis may include vancomycin alone or in combination with an aminoglycoside, such as gentamicin, depending on the suspected causative organisms and local epidemiology and susceptibility patterns 2.

• Vancomycin is effective against staphylococcal endocarditis and may be used as initial therapy when methicillin-resistant staphylococci are suspected.
• Gentamicin may be considered as initial therapy in conjunction with a penicillin-type or cephalosporin-type drug for the treatment of endocarditis caused by gram-negative organisms or group D streptococci 3.

From the Research

Empiric Treatment for Infective Endocarditis

The first line empirical treatment for infective endocarditis is not explicitly stated in the provided studies, but the following information can be gathered:

• Empiric antibiotics should be targeted toward the most likely pathogens, including staphylococci, streptococci, and enterococci species 4.
• In urgent cases where empiric antimicrobial therapy is necessary before the causative organism is identified, a combination of aqueous penicillin G, nafcillin, and gentamicin is effective therapy 5.
• The use of aminoglycosides for the treatment of endocarditis has been dramatically reduced over the last 20 years, and it should be administered once daily, and no longer than 2 weeks 6.

Treatment Based on Causative Microorganism

The treatment of infective endocarditis is guided by identification of the causative micro-organism, and the following treatments are recommended:

• For streptococcal endocarditis: aqueous penicillin G alone for four weeks or combined penicillin and streptomycin for two weeks 5.
• For enterococcal endocarditis: a combination of aqueous penicillin G together with either streptomycin or gentamicin for four to six weeks 5.
• For staphylococcal endocarditis: anti-staphylococcal penicillins, such as nafcillin or oxacillin, with or without gentamicin 7, 8, 6.
• For prosthetic valve staphylococcal endocarditis: nafcillin (or oxacillin) with rifampicin and gentamicin 7, 6.

Key Points

• The choice of antibiotic therapy for bacterial endocarditis is determined by the identity and antibiotic susceptibility of the infecting organism, the type of cardiac valve involved, and characteristics of the patient 8.
• Vancomycin should be substituted for penicillin when high-level resistance is present 7, 8.
• The optimal duration of antibacterial treatment is 4 weeks for most native valve endocarditis, and 6 weeks for prosthetic-valve endocarditis 6.