What is the recommended treatment for a urinary tract infection caused by Enterococcus faecalis?

Treatment of Urinary Tract Infections Caused by Enterococcus faecalis

For uncomplicated urinary tract infections caused by Enterococcus faecalis, amoxicillin 500 mg orally every 8 hours for 7 days is the recommended first-line therapy. 1

First-Line Treatment Options

• Amoxicillin 500 mg orally every 8 hours for 7 days is the first-line treatment for pansensitive E. faecalis UTIs, with high clinical (88.1%) and microbiological (86%) eradication rates 1, 2
• Ampicillin 500 mg orally every 8 hours for 7 days is an equivalent alternative to amoxicillin with similar efficacy 1, 2
• For inpatients requiring IV therapy, ampicillin 2 g IV every 4 hours is recommended 3

Alternative Treatment Options

• Fosfomycin 3 g as a single oral dose is FDA-approved specifically for E. faecalis UTIs and offers convenient single-dose therapy 3, 2
• Nitrofurantoin 100 mg orally every 6 hours for 7 days is an effective alternative with good in vitro activity against E. faecalis and low resistance rates 3, 1
• For penicillin-allergic patients, nitrofurantoin or fosfomycin should be considered as first alternatives 1, 4

Treatment of Vancomycin-Resistant E. faecalis (VRE)

For VRE UTIs, the following options are recommended in order of preference:

1. A single dose of fosfomycin 3 g PO for uncomplicated UTIs 3
2. Nitrofurantoin 100 mg PO every 6 hours for uncomplicated UTIs 3
3. High-dose ampicillin (18-30 g IV daily in divided doses) or amoxicillin 500 mg PO/IV every 8 hours for uncomplicated UTIs if susceptible 3
4. Linezolid 600 mg IV or PO every 12 hours for complicated UTIs 3, 5

Important Considerations

• Confirm susceptibility testing before initiating therapy, even for strains described as "pansensitive" 1, 2
• Avoid fluoroquinolones due to high resistance rates (46-47% for ciprofloxacin/levofloxacin) and unfavorable risk-benefit profile for uncomplicated UTIs 2, 6
• For beta-lactamase producing strains, consider replacing amoxicillin with amoxicillin-clavulanate for 7 days 1, 5
• Differentiate between colonization and true infection to avoid unnecessary antibiotic use, particularly in catheterized patients 3, 7

Special Populations

• For complicated UTIs or pyelonephritis, longer treatment durations may be necessary 1
• For patients with hospital-acquired infections, prior healthcare center exposure, or treatment in urological departments, be aware of increased risk of fluoroquinolone resistance 6
• For severe infections with bacteremia, consider high-dose daptomycin (8-12 mg/kg/day) for VRE strains 3

Treatment Algorithm

1. Obtain urine culture and susceptibility testing
2. For uncomplicated UTI with susceptible E. faecalis:
   • First choice: Amoxicillin or ampicillin 500 mg PO every 8 hours for 7 days 1, 2
   • Penicillin allergy: Nitrofurantoin 100 mg PO every 6 hours for 7 days or fosfomycin 3 g single dose 3, 1
3. For VRE UTI:
   • Uncomplicated: Fosfomycin 3 g single dose or nitrofurantoin 100 mg PO every 6 hours 3
   • Complicated: Linezolid 600 mg PO/IV every 12 hours 3, 5

Remember that removal of urinary catheters should be considered when possible, as this may resolve the infection without antibiotics in catheter-associated UTIs 4.