What antibiotics cover Enterococcus faecalis?

From the Guidelines

Ampicillin or amoxicillin, in combination with gentamicin, is the recommended antibiotic regimen for treating Enterococcus faecalis infections, as per the 2015 ESC guidelines for the management of infective endocarditis 1. The dosage for ampicillin or amoxicillin is 200 mg/kg/day i.v. in 4 –6 doses, and for gentamicin, it is 3 mg/kg/day i.v. or i.m. in 1 dose, with a treatment duration of 6 weeks for patients with symptoms or prosthetic valve endocarditis. Some key points to consider when treating Enterococcus faecalis infections include:

• The combination of ampicillin and gentamicin is active against Enterococcus faecalis strains with and without high-level aminoglycoside resistance (HLAR) 1.
• Vancomycin-based regimens can be used as an alternative, especially in cases of beta-lactam resistance or multiresistance to aminoglycosides, beta-lactams, and vancomycin 1.
• It is essential to monitor serum levels of aminoglycosides and renal function, as well as serum vancomycin concentrations, during treatment 1.
• The treatment duration may vary depending on the infection site and severity, with 6 weeks being recommended for endocarditis and 2-6 weeks for other infections 1.
• Antibiotic susceptibility testing is crucial before initiating therapy, as resistance patterns can vary 1.

From the FDA Drug Label

Linezolid has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections... Aerobic and facultative Gram-positive microorganisms... Enterococcus faecalis (including vancomycin-resistant strains) At least 90% of the following microorganisms exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoint for linezolid... Enterococcus faecalis (including vancomycin-resistant strains) Table 4 Susceptibility Interpretive Criteria for Linezolid... Enterococcus spp≤ 2 4≥ 23 2 1–22≤20

Antibiotics that cover Enterococcus faecalis include:

• Linezolid The minimum inhibitory concentration (MIC) for Enterococcus spp is ≤ 4, and the disk diffusion zone diameter is ≥ 23. 2

From the Research

Antibiotics for Enterococcus faecalis Infections

The following antibiotics have been studied for their effectiveness against Enterococcus faecalis infections:

• Ampicillin-ceftriaxone combination, which has been shown to be effective in treating orthopedic infections due to E. faecalis 3
• Ampicillin, vancomycin, and linezolid, which have been tested for their activity against enterococcal biofilms, with high concentrations required to inhibit biofilm growth 4
• Ciprofloxacin or linezolid in combination with rifampicin, which have been found to be effective against E. faecalis biofilms in vitro 5
• Penicillin-gentamicin and dual beta-lactam therapies, such as ampicillin and ceftriaxone, which are recommended as first-line regimens for E. faecalis infective endocarditis 6, 7

Combination Therapies

Combination therapies have been found to be effective in treating E. faecalis infections, including:

• Ampicillin-ceftriaxone combination, which has been shown to be effective in treating orthopedic infections due to E. faecalis 3
• Ciprofloxacin or linezolid in combination with rifampicin, which have been found to be effective against E. faecalis biofilms in vitro 5
• Penicillin-gentamicin and dual beta-lactam therapies, such as ampicillin and ceftriaxone, which are recommended as first-line regimens for E. faecalis infective endocarditis 6, 7

Treatment Outcomes

Treatment outcomes for E. faecalis infections have been found to vary depending on the antibiotic regimen used, with:

• High mortality rates associated with E. faecalis infective endocarditis, despite treatment with combination antibiotics 6
• Adverse events requiring treatment modification, such as nephrotoxicity, being more common with penicillin-gentamicin therapy compared to dual beta-lactam therapy 7