Treatment of Enterococcus faecalis UTI (>100,000 CFU/mL)
For urinary tract infections with Enterococcus faecalis greater than 100,000 CFU/mL, amoxicillin 500 mg orally every 8 hours for 7 days is the first-line treatment, achieving 88.1% clinical and 86% microbiological eradication rates. 1, 2
First-Line Oral Treatment Options
Amoxicillin 500 mg orally every 8 hours for 7 days is the preferred first-line therapy recommended by the American College of Physicians for uncomplicated E. faecalis UTIs 1, 2
Ampicillin 500 mg orally every 8 hours for 7 days is an equivalent alternative with similar efficacy 1, 2
For hospitalized patients requiring IV therapy, ampicillin 2 g IV every 4 hours (or high-dose ampicillin 18-30 g IV daily in divided doses) is recommended by the Infectious Diseases Society of America to achieve sufficient urinary concentrations 1, 2
Alternative Oral Agents
Fosfomycin 3 g as a single oral dose is FDA-approved specifically for E. faecalis UTIs and offers convenient single-dose therapy for uncomplicated infections 1, 2
Nitrofurantoin 100 mg orally every 6 hours for 7 days has good in vitro activity against E. faecalis with resistance rates below 6% 1, 2
Critical Clinical Considerations Before Treatment
Always obtain susceptibility testing before initiating therapy, even for strains described as "pansensitive," as resistance patterns vary significantly by institution 1, 2
Differentiate true infection from asymptomatic bacteriuria - colonization with E. faecalis does not routinely require treatment 1
Avoid fluoroquinolones due to high resistance rates (46-47% for ciprofloxacin/levofloxacin) and unfavorable risk-benefit profile 2
Treatment Duration
7 days is the standard duration for uncomplicated E. faecalis UTI 1, 2
Longer durations may be necessary for complicated UTIs or pyelonephritis, though specific evidence for E. faecalis is limited 2
Special Populations and Resistant Strains
For beta-lactamase producing strains, replace amoxicillin with amoxicillin-clavulanate for 7 days 1
For penicillin allergy, nitrofurantoin 100 mg orally every 6 hours for 7 days is appropriate 1
For vancomycin-resistant E. faecalis (VRE), fosfomycin 3 g single dose or nitrofurantoin 100 mg every 6 hours are recommended by the Infectious Diseases Society of America 2
Important Clinical Context
E. faecalis accounts for approximately 25% of recurrent UTIs (after E. coli) and is particularly common in patients with risk factors for complicated UTIs 3
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 1
E. faecalis demonstrates tropism for the kidneys over the bladder in urinary tract infections, which may influence clinical presentation 4
Recent studies show E. faecalis UTIs are associated with hospitalization, urinary catheter use, and recent antibiotic use within 3 months 5