What is the recommended treatment for a urinary tract infection (UTI) caused by Enterococcus?

Treatment of Enterococcus Urinary Tract Infections

For urinary tract infections caused by Enterococcus species, nitrofurantoin (100mg twice daily for 5 days) or fosfomycin (3g single dose) are the recommended first-line treatments for uncomplicated lower UTIs. 1

Treatment Algorithm Based on Infection Type

Uncomplicated Lower UTI (Cystitis)

• First-line options:
  • Nitrofurantoin 100mg twice daily for 5 days 1
  • Fosfomycin 3g single oral dose 1
  • Trimethoprim-sulfamethoxazole 160/800mg twice daily for 3 days (if susceptible) 1

Complicated UTI or Pyelonephritis

• Treatment duration: 7-14 days 1
• For susceptible strains:
  • Ampicillin (preferred for ampicillin-susceptible strains) 1, 2
  • Amoxicillin (alternative to ampicillin) 2

Vancomycin-Resistant Enterococcus (VRE) UTIs

• For lower tract VRE UTIs:

  • Nitrofurantoin, fosfomycin, or doxycycline (if susceptible) 2

• For upper tract or bacteremic VRE UTIs:

  • Linezolid (indicated for VRE faecium infections, including cases with bacteremia) 3, 2
  • Daptomycin (for ampicillin-resistant strains) 2

Antibiotic Selection Considerations

Susceptibility Patterns

• Enterococci have intrinsic resistance to cephalosporins, making these ineffective 1
• E. faecalis is generally more susceptible to antibiotics than E. faecium 1
• High rates of fluoroquinolone resistance have been observed in E. faecalis strains 1
• Emerging resistance to nitrofurantoin has been observed, with rates increasing from near zero to 40% in some studies 4

Special Considerations

• Aminopenicillins may be effective for lower UTIs even when in vitro testing shows resistance, due to high urinary concentrations 5
• For multidrug-resistant strains, fosfomycin has demonstrated high activity against common UTI pathogens including Enterococcus faecalis 6
• Linezolid should be reserved for confirmed upper tract or bacteremic VRE UTIs 2

Treatment Duration

• Uncomplicated lower UTIs: 5-7 days 1
• Complicated infections or pyelonephritis: 7-14 days 1

Follow-up Recommendations

• Obtain follow-up culture 1-2 weeks after completing therapy if symptoms persist 1
• If bacteriuria recurs after treatment, select an alternative agent rather than repeating the same antibiotic 1
• Infectious disease consultation is highly recommended for managing infections caused by multidrug-resistant organisms 1

Common Pitfalls to Avoid

1. Treating asymptomatic bacteriuria: Unnecessary use of antibiotics in patients simply colonized with VRE in the urine has become a significant problem in hospitals and long-term care facilities 2

2. Using cephalosporins: Enterococci have intrinsic resistance to cephalosporins, making these ineffective regardless of susceptibility testing results 1

3. Overuse of broad-spectrum agents: Reserve linezolid and daptomycin for confirmed upper tract or bacteremic VRE UTIs to prevent development of resistance 2

4. Inadequate treatment duration: Ensure at least 5-7 days of therapy for uncomplicated UTIs and 7-14 days for complicated infections to ensure complete bacterial eradication 1

5. Failure to remove indwelling catheters: Consider removal of indwelling urinary catheters when possible, as this can be a source of persistent infection 7