From the Guidelines
Ampicillin or amoxicillin are the first-line antibiotics for treating uncomplicated Enterococcus faecalis urinary tract infections (UTIs), typically prescribed at 500 mg orally three times daily for 7-10 days. For patients with penicillin allergies, nitrofurantoin (100 mg orally twice daily for 5-7 days) or fosfomycin (3 g single oral dose) are effective alternatives 1. The choice of antibiotic should be guided by susceptibility testing whenever possible, as resistance patterns can vary.
Key Considerations
- High dose ampicillin (18-30 g IV daily in divided doses) or amoxicillin (500 mg IV or PO every 8 h daily) is recommended for uncomplicated urinary tract infections due to VRE 1.
- Nitrofurantoin 100 mg PO every 6 h is recommended for the treatment of uncomplicated urinary tract infections due to VRE 1.
- Fosfomycin 3 g PO is recommended for uncomplicated urinary tract infections due to VRE 1.
Treatment Approach
Patients should complete the full course of antibiotics even if symptoms improve quickly, and should increase fluid intake to help flush bacteria from the urinary tract. Follow-up urine cultures may be necessary to confirm clearance of the infection, especially in complicated cases or recurrent infections.
Resistance and Susceptibility
E. faecalis is naturally resistant to many antibiotics including cephalosporins and trimethoprim-sulfamethoxazole, which is why targeted therapy is essential 1.
Special Considerations
In cases of complicated infections or resistance, combination therapy with ampicillin plus gentamicin may be necessary, or vancomycin (15-20 mg/kg IV every 12 hours) for severe infections 1.
From the FDA Drug Label
Daptomycin has been shown to be active against most isolates of the following microorganisms both in vitro and in clinical infections [see Indications and Usage (1)] Gram-Positive Bacteria Enterococcus faecalis (vancomycin-susceptible isolates only)
Daptomycin is effective against vancomycin-susceptible Enterococcus faecalis. However, it is essential to note that the susceptibility of the specific E. faecalis isolate to daptomycin should be confirmed through susceptibility testing.
- The FDA drug label does not provide information on the treatment of E. faecalis UTI specifically, but it does indicate that daptomycin is active against vancomycin-susceptible E. faecalis isolates.
- Key considerations:
- Vancomycin susceptibility: Daptomycin is only effective against vancomycin-susceptible E. faecalis isolates.
- Susceptibility testing: Necessary to confirm the effectiveness of daptomycin against the specific E. faecalis isolate. 2
From the Research
Antibiotic Treatment Options for Enterococcus faecalis UTI
- The choice of antibiotic for treating Enterococcus faecalis UTI depends on the susceptibility pattern of the isolate 3, 4, 5, 6, 7.
- Ampicillin is generally considered the drug of choice for ampicillin-susceptible enterococcal UTIs, including those caused by Enterococcus faecalis 3, 7.
- Nitrofurantoin, fosfomycin, and doxycycline have intrinsic activity against enterococci, including vancomycin-resistant Enterococcus faecalis, and are possible oral options for treating UTIs caused by this organism 3, 4, 5.
- Linezolid and daptomycin should be reserved for confirmed or suspected upper and/or bacteremic UTIs among ampicillin-resistant strains 3, 4.
- Vancomycin-resistant Enterococcus faecalis isolates are often susceptible to ampicillin, linezolid, and nitrofurantoin, but less susceptible to ciprofloxacin and tetracycline 5, 6.
Specific Antibiotic Susceptibility Patterns
- Vancomycin-resistant Enterococcus faecalis isolates are >90% susceptible to ampicillin, linezolid, and nitrofurantoin 5.
- Fosfomycin susceptibility rates are around 86% for vancomycin-resistant Enterococcus faecalis isolates 5.
- Ampicillin and nitrofurantoin may be considered for urinary tract infections secondary to vancomycin-resistant Enterococcus faecalis, Enterococcus casseliflavus, and Enterococcus gallinarum 5.
Treatment Outcomes
- Clinical cure rates of around 88.1% and microbiological eradication rates of around 86% have been reported for patients with complicated UTIs caused by vancomycin-resistant Enterococcus spp, including Enterococcus faecalis, treated with ampicillin 7.