Treatment of E. faecalis UTI in Pregnancy
For pregnant women with E. faecalis urinary tract infection, use amoxicillin 500 mg orally every 8 hours for 7 days or ampicillin 500 mg orally every 8 hours for 7 days as first-line therapy, achieving clinical eradication rates of 88.1% and microbiological eradication of 86%. 1
Screening and Treatment Rationale
All pregnant women must be screened for and treated for asymptomatic bacteriuria (ASB), including E. faecalis, at an initial early pregnancy visit. 2 This is critical because:
- Untreated ASB progresses to pyelonephritis in 20-35% of cases 2
- Treatment reduces pyelonephritis risk from 20-35% to 1-4% 2
- Treatment may reduce preterm birth (from 53 per 1000 to 14 per 1000) and very low birth weight (from 137 per 1000 to 88 per 1000) 1
- Treatment probably reduces the risk of low birth weight and preterm labor 2
First-Line Treatment Options
Ampicillin/Amoxicillin Regimens:
- Amoxicillin 500 mg orally every 8 hours for 7 days (preferred oral option) 1, 3
- Ampicillin 500 mg orally every 8 hours for 7 days 1, 3
- 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 1
Ampicillin achieves high urinary concentrations that can overcome even intermediate susceptibility patterns in laboratory testing, making it highly effective for E. faecalis UTI 3. For beta-lactamase producing strains, replace amoxicillin with amoxicillin-clavulanate for 7 days 1.
Treatment Duration
Use 4-7 days of antimicrobial treatment rather than shorter duration. 2, 1 Single-dose therapy is inferior to 4-7 day courses, with one study showing 7 days of nitrofurantoin was more effective than single-dose in preventing lower birth weight (RR 1.65,95% CI 1.06-2.57) 2. The optimal duration varies by antimicrobial agent; nitrofurantoin and β-lactams are less effective as short-course therapy compared to their use in non-pregnant women with acute cystitis 2.
Alternative Options for Penicillin Allergy
Nitrofurantoin 100 mg orally every 6 hours for 7 days is the preferred alternative for penicillin-allergic patients 1. Nitrofurantoin has:
- Good in vitro activity against E. faecalis with resistance rates below 6% 1
- FDA approval for UTIs caused by E. faecalis 1, 3
- Safety during the second trimester of pregnancy 3
Fosfomycin 3 g orally as a single dose can be used for uncomplicated E. faecalis UTI 1, 3. It is FDA-approved specifically for UTI caused by E. faecalis and has a favorable safety profile during pregnancy 3.
Critical Clinical Caveats
Always obtain susceptibility testing before initiating therapy, even for strains described as "pansensitive," as resistance patterns vary significantly 1. This is particularly important because:
- E. faecalis resistance to ampicillin, nitrofurantoin, and ciprofloxacin varies 4
- High rates of multidrug resistance exist in hospitalized patients 4
- E. faecalis can form biofilms that reduce treatment efficacy and may contribute to relapse 5, 6
Avoid fluoroquinolones due to high resistance rates (46-47%) and teratogenic concerns in pregnancy 1.
Differentiate true infection from colonization before prescribing antibiotics 1. However, in pregnancy, even asymptomatic bacteriuria with E. faecalis requires treatment, unlike in non-pregnant patients 2, 1.
Aminoglycosides (gentamicin) should be used cautiously and only for severe infections due to nephrotoxicity and ototoxicity risks 3.
Management of Recurrent Infections
For recurrent UTIs after initial treatment, consider:
- Prophylaxis with daily low-dose nitrofurantoin (if <36 weeks gestation) or cephalexin 3
- Ensure adequate hydration during treatment 3
- Remove indwelling urinary catheters if present 7
The need for additional antibiotics for E. faecalis relapse is relatively uncommon (10-14% in various populations), with no significant difference between premenopausal and postmenopausal patients 5.