What is the recommended duration and route of treatment for Enterococcus faecalis bacteremia, specifically whether it should be treated with intravenous (IV) or oral antibiotics?

From the Guidelines

The recommended treatment for Enterococcus faecalis bacteremia typically requires 4-6 weeks of antibiotic therapy, with the initial treatment being intravenous (IV) antibiotics. The standard regimen consists of ampicillin (2g IV every 4-6 hours) or penicillin G, often combined with gentamicin (1mg/kg IV every 8 hours) for synergistic effect in serious infections, as suggested by 1 and 1. For uncomplicated cases with source control and clinical improvement, some patients may be transitioned to oral therapy after 1-2 weeks of IV treatment, typically with amoxicillin (1g orally three times daily). However, complicated infections such as endocarditis, osteomyelitis, or those involving prosthetic devices generally require the full course of IV therapy. Key considerations for treatment duration and route include:

• The ability to tolerate β-lactam therapy
• The presence of normal or impaired renal function
• The presence of abnormal cranial nerve VIII function
• The availability of rapid streptomycin serum concentrations
• The minimum duration of therapy, which is typically 6 weeks for native valve infection with symptoms of infection >3 months, prosthetic valve endocarditis (PVE), or treatment with a double β-lactam regimen, as outlined in 1. For penicillin-allergic patients, vancomycin (15-20mg/kg IV every 12 hours) is the alternative treatment. Blood cultures should be repeated to confirm clearance of bacteremia, and echocardiography is recommended to rule out endocarditis, as these infections can have severe consequences on morbidity, mortality, and quality of life if not properly managed. The extended duration of therapy is necessary because E. faecalis infections are often difficult to eradicate due to the organism's intrinsic resistance mechanisms and ability to form biofilms, particularly in the presence of foreign bodies or damaged heart valves. In cases where the strain of Enterococcus is susceptible to both gentamicin and streptomycin, it is reasonable to use 6 weeks of vancomycin-gentamicin therapy, as suggested by 1. Ultimately, the treatment approach should be individualized based on the patient's specific clinical presentation, the results of antimicrobial susceptibility testing, and the presence of any underlying medical conditions that may impact treatment outcomes.

From the Research

Treatment Duration and Route for Enterococcus faecalis Bacteremia

• The recommended duration of treatment for Enterococcus faecalis bacteremia is not explicitly stated in the provided studies, but it can be inferred that the treatment duration may vary depending on the complexity of the infection and the patient's response to therapy 2, 3, 4.
• A study published in 2018 suggests that a 4-week course of antibiotic treatment may not be suitable for uncomplicated native valve Enterococcus faecalis infective endocarditis, and that a 6-week course may be more effective in preventing relapses 4.
• Another study published in 2025 found that sequential oral therapy for E. faecalis bloodstream infections had similar outcomes compared to IV-only treatment, and may be considered in eligible patients 3.

Route of Treatment

• The route of treatment for Enterococcus faecalis bacteremia can be either intravenous (IV) or oral, depending on the severity of the infection and the patient's condition 2, 3.
• IV antibiotics are often considered the standard of care for treatment of bloodstream infections, but recent literature has shown that sequential oral therapy can be non-inferior to IV antibiotics for certain pathogens and disease states 3.
• A study published in 2025 found that hospital length of stay was significantly longer in patients receiving IV-only therapy compared to those receiving sequential oral therapy 3.

Antibiotic Options

• Aminopenicillins are preferred over other agents when enterococci are susceptible and patients can tolerate them 2.
• Daptomycin and linezolid have demonstrated clinical efficacy against vancomycin-resistant enterococci (VRE) 2, 5.
• Teicoplanin, vancomycin, linezolid, and nitrofurantoin are recommended against E. faecalis species based on antibiogram results 6.