Treatment for Enterococcus faecalis in Urine
For uncomplicated urinary tract infections caused by Enterococcus faecalis, amoxicillin 500 mg orally every 8 hours for 7 days is the first-line treatment, achieving clinical and microbiological eradication rates of 88.1% and 86%, respectively. 1
First-Line Treatment Options
Ampicillin/Amoxicillin remains the drug of choice for enterococcal urinary tract infections 2:
- Amoxicillin 500 mg orally every 8 hours for 7 days is recommended as first-line therapy for uncomplicated E. faecalis UTIs 1
- Ampicillin 500 mg orally every 8 hours for 7 days is an equivalent alternative with similar efficacy 1
- For hospitalized patients requiring IV therapy, high-dose ampicillin (18-30 g IV daily in divided doses) or amoxicillin 500 mg IV every 8 hours is recommended to achieve sufficient urinary concentrations 2
The high urinary concentrations of ampicillin can overcome high ampicillin MICs in ampicillin-resistant VRE strains, making it effective even when in vitro susceptibility testing suggests resistance 2. This is a critical clinical pearl—ampicillin may still work for urinary tract infections despite reported resistance.
Alternative Oral Agents
When ampicillin/amoxicillin cannot be used, several alternatives exist:
- Nitrofurantoin 100 mg orally every 6 hours for 7 days has good in vitro activity against E. faecalis with resistance rates below 6% 2, 1
- Fosfomycin 3 g orally as a single dose is FDA-approved specifically for UTI caused by E. faecalis and is recommended for uncomplicated infections 2
For patients with penicillin allergy, nitrofurantoin is the appropriate alternative 1.
Agents to Avoid
Fluoroquinolones should NOT be used due to high resistance rates (46-47% for ciprofloxacin/levofloxacin) and unfavorable risk-benefit ratios for uncomplicated UTIs 1, 3. Ciprofloxacin resistance is particularly high in hospital-acquired infections and patients transferred from healthcare centers 3.
Treatment for Complicated UTI or Pyelonephritis
For complicated infections requiring parenteral therapy:
- Ampicillin 2 g IV every 4 hours remains the standard approach 2
- Ampicillin-sulbactam can be used and maintains good activity against E. faecalis 3
- For beta-lactamase producing strains, consider amoxicillin-clavulanate 1
Vancomycin in combination with an aminoglycoside is effective for E. faecalis endocarditis but is not typically necessary for isolated urinary tract infections 4.
Critical Clinical Considerations
Always obtain susceptibility testing before initiating therapy, even for strains described as "pansensitive" 1. This is essential because:
- Resistance patterns vary significantly by institution and patient population
- Hospital-acquired infections have substantially higher fluoroquinolone resistance 3
- Ampicillin may work despite reported resistance in urinary tract infections 2
Differentiate colonization from true infection before prescribing anti-enterococcal agents 2. Asymptomatic bacteriuria with E. faecalis does not routinely require treatment 5.
Remove indwelling urinary catheters when possible, as catheterization is associated with enterococcal UTI 5.