From the Guidelines
Ampicillin is the recommended first-line antibiotic for treating Enterococcus faecalis infections, typically given at 200 mg/kg/day i.v. in 4 –6 doses, in combination with gentamicin 3 mg/kg/day i.v. or i.m. in 1 dose, for 6 weeks. This recommendation is based on the 2015 ESC guidelines for the management of infective endocarditis 1. The combination of ampicillin and gentamicin is active against Enterococcus faecalis strains with and without high-level aminoglycoside resistance (HLAR), making it the combination of choice in patients with HLAR E. faecalis endocarditis. Some key points to consider when treating E. faecalis infections include:
- Monitoring serum levels of aminoglycosides and renal function as indicated in Table 16 1
- Using vancomycin-based regimens for beta-lactam resistance due to PBP5 alteration 1
- Considering alternative treatments, such as daptomycin plus ampicillin or linezolid, for multiresistance to aminoglycosides, beta-lactams, and vancomycin 1
- Treatment duration varies by infection site, with 6 weeks recommended for endocarditis 1 It is essential to note that E. faecalis has intrinsic resistance to many antibiotics, including cephalosporins and clindamycin, making proper antibiotic selection crucial 1. Susceptibility testing should guide therapy, especially given increasing resistance concerns.
From the FDA Drug Label
Fosfomycin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section: Aerobic gram-positive microorganisms Enterococcus faecalis
Daptomycin has been shown to be active against most isolates of the following microorganisms both in vitro and in clinical infections [see Indications and Usage (1)] Gram-Positive Bacteria Enterococcus faecalis (vancomycin-susceptible isolates only)
- Fosfomycin and Daptomycin are two antibiotics that have shown activity against Enterococcus faecalis.
- Fosfomycin is effective against E. faecalis in general, while Daptomycin is effective against vancomycin-susceptible isolates of E. faecalis.
- The choice of antibiotic may depend on the specific circumstances of the infection and the susceptibility of the isolate 2 3.
From the Research
Antibiotic Options for E. faecalis
- Aminopenicillins are preferred over other agents when E. faecalis is susceptible and patients can tolerate them 4
- Daptomycin and linezolid have demonstrated clinical efficacy against vancomycin-resistant E. faecalis (VRE) 4, 5, 6
- Synergistic combinations of antibiotics are often warranted in complex infections, while monotherapies are generally appropriate for uncomplicated infections 4
- For cystitis, amoxicillin, nitrofurantoin, or fosfomycin are ideal options 4, 7
- Fosfomycin has shown synergy with amoxicillin, daptomycin, and linezolid against VRE in vitro 8
Specific Antibiotic Considerations
- Daptomycin may be considered a promising antibacterial agent for the treatment of complicated UTI caused by gram-positive uropathogens, including E. faecalis 5
- Linezolid has been shown to have lower mortality rates compared to daptomycin for the treatment of VRE bacteremia 6
- Quinupristin/dalfopristin and tigecycline have limited clinical data and potential pharmacokinetic and safety issues for severe infections 4