What is the recommended treatment for Enterococcus faecalis (E. faecalis) urinary tract infections (UTIs) in pregnancy?

Treatment of Enterococcus faecalis UTI in Pregnancy

For Enterococcus faecalis UTI in pregnancy, treat with 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. 1, 2

First-Line Treatment Options

• Amoxicillin/ampicillin remains the drug of choice for enterococcal UTIs in pregnancy, with amoxicillin 500 mg orally every 8 hours achieving high clinical (88.1%) and microbiological (86%) eradication rates 1
• Ampicillin is specifically recommended as the treatment of choice for enterococcal infections, particularly urinary tract infections in obstetric patients 2
• E. faecalis demonstrates 92.9% susceptibility to ampicillin, making it highly effective 3
• For hospitalized patients requiring IV therapy, use high-dose ampicillin 18-30 g IV daily in divided doses or amoxicillin 500 mg IV every 8 hours 1

Alternative Treatment Options for Penicillin Allergy

• Nitrofurantoin 100 mg orally every 6 hours for 7 days is the preferred alternative for patients with penicillin allergy 1
• Nitrofurantoin has good in vitro activity against E. faecalis with resistance rates below 6% and maintains low resistance (7.7%) 1, 3
• Nitrofurantoin is safe for treating VRE UTIs in pregnancy if the organism is susceptible 4

Additional Alternative Agents

• Fosfomycin 3 g orally as a single dose is FDA-approved specifically for UTI caused by E. faecalis and can be used for uncomplicated infections 1
• For beta-lactamase producing strains, replace amoxicillin with amoxicillin-clavulanate for 7 days 1

Treatment Duration

• Standard duration is 7 days for uncomplicated E. faecalis UTI in pregnancy 1, 5
• For asymptomatic bacteriuria in pregnancy, single-dose therapy with an antimicrobial to which the organism is susceptible may be adequate 5
• Treatment duration should be based on clinical response, with longer durations possibly necessary for complicated UTI 1

Critical Pregnancy-Specific Considerations

• All pregnant women should be screened for and treated for asymptomatic bacteriuria to prevent progression to pyelonephritis, which occurs in 20-35% of untreated cases 6
• Screening with urine culture should be collected at one of the initial visits early in pregnancy 6
• Treatment of asymptomatic bacteriuria in pregnancy reduces pyelonephritis risk and 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) 6
• Recommend 4-7 days of antimicrobial treatment rather than shorter duration for pregnant women with asymptomatic bacteriuria 6

Important Clinical Caveats

• Always obtain susceptibility testing before initiating therapy, even for strains described as "pansensitive," as resistance patterns vary significantly 1
• Differentiate colonization from true infection before prescribing anti-enterococcal agents, as asymptomatic bacteriuria with E. faecalis does not routinely require treatment unless the patient is pregnant 1
• Avoid fluoroquinolones due to high resistance rates (46-47%) and teratogenic concerns in pregnancy 1
• Repeat urine cultures seven days following therapy to assess cure or failure 5
• High urinary concentrations of ampicillin can overcome high ampicillin MICs even in ampicillin-resistant VRE strains 1

Management of Vancomycin-Resistant E. faecalis (VRE)

• For VRE UTI in pregnancy where nitrofurantoin is not effective, daptomycin 4 mg/kg daily can be used safely (pregnancy category B) with high urinary concentrations 4
• Linezolid, doxycycline, and quinupristin/dalfopristin have teratogenic risk or unknown safety profiles and should be avoided 4