What antibiotic is effective against Enterococcus faecalis in a urine culture?

From the Guidelines

Ampicillin or amoxicillin is the first-line treatment for uncomplicated urinary tract infections caused by Enterococcus faecalis, typically dosed at 500 mg orally three times daily for 7 days, as recommended by recent guidelines 1. When considering the treatment of Enterococcus faecalis infections, particularly in the context of urinary tract infections, it's crucial to prioritize the most effective and least resistant options.

• The choice between ampicillin and amoxicillin often depends on the patient's specific condition, potential allergies, and the severity of the infection.
• For patients with penicillin allergies, alternatives such as nitrofurantoin (100 mg orally twice daily for 5-7 days) or fosfomycin (3 g single oral dose) are recommended 1.
• In cases of complicated infections or pyelonephritis, combination therapy with ampicillin plus gentamicin may be necessary, or vancomycin (15-20 mg/kg IV every 12 hours) for resistant strains.
• It's essential to guide treatment by susceptibility testing since E. faecalis can develop resistance to multiple antibiotics 1.
• Patients should complete the full course of antibiotics even if symptoms improve quickly, drink plenty of fluids during treatment, and follow up if symptoms persist after completing therapy.
• E. faecalis has intrinsic resistance to cephalosporins and trimethoprim-sulfamethoxazole, which should be avoided despite their common use for other urinary pathogens 1.

From the FDA Drug Label

Tigecycline: Gram-positive bacteria: Enterococcus faecalis (vancomycin-susceptible isolates) Daptomycin: Gram-Positive Bacteria: Enterococcus faecalis (vancomycin-susceptible isolates only)

Antibiotic options for urine culture with Enterococcus faecalis:

• Tigecycline: may be effective against vancomycin-susceptible isolates of Enterococcus faecalis
• Daptomycin: may be effective against vancomycin-susceptible isolates of Enterococcus faecalis

Note: The effectiveness of these antibiotics may depend on the specific susceptibility of the Enterococcus faecalis isolate and the clinical context of the infection. 2 3

From the Research

Antibiotic Options for Urine Culture with Enterococcus faecalis

• The choice of antibiotic for Enterococcus faecalis in urine culture depends on the susceptibility profile of the isolate 4, 5, 6.
• According to a study published in 2024, vancomycin-resistant E. faecalis isolates were >90% susceptible to ampicillin, linezolid, and nitrofurantoin, but <10% susceptible to ciprofloxacin and tetracycline 4.
• Another study published in 2010 suggested that ampicillin, nitrofurantoin, and fosfomycin may be considered for urinary tract infections secondary to vancomycin-resistant E. faecalis 5.
• A review published in 2010 recommended ampicillin as the drug of choice for ampicillin-susceptible enterococcal UTIs, including VRE, and suggested nitrofurantoin, fosfomycin, and doxycycline as possible oral options for VRE cystitis 6.
• A study published in 2005 found that all E. faecalis strains isolated from children with community-acquired UTIs were susceptible to ampicillin, vancomycin, and nitrofurantoin 7.

Specific Antibiotic Recommendations

• Ampicillin may be considered for urinary tract infections secondary to vancomycin-resistant E. faecalis, E. casseliflavus, and E. gallinarum 4, 6.
• Nitrofurantoin may be considered for urinary tract infections secondary to vancomycin-resistant E. faecalis, E. casseliflavus, and E. gallinarum 4, 5, 6.
• Linezolid may be considered for confirmed or suspected upper and/or bacteremic VRE UTIs among ampicillin-resistant strains 6.
• Fosfomycin may be considered for urinary tract infections secondary to vancomycin-resistant E. faecalis, with a susceptibility rate of 86% 4.