What are the treatment options for a urinary tract infection (UTI) caused by Enterococcus?

Treatment Options for UTIs Caused by Enterococcus

For urinary tract infections caused by Enterococcus, the recommended first-line treatments include fosfomycin, nitrofurantoin, or ampicillin/amoxicillin (if susceptible), with treatment duration based on infection complexity and patient factors. 1

First-Line Treatment Options for Uncomplicated UTI

• Fosfomycin 3g oral powder as a single dose is effective for uncomplicated UTIs caused by Enterococcus, particularly for vancomycin-resistant enterococci (VRE) 2, 1
• Nitrofurantoin 100mg PO every 6 hours is recommended for uncomplicated UTIs due to VRE with good activity against Enterococcus species 2, 1
• Ampicillin/Amoxicillin (high dose ampicillin 18-30g IV daily in divided doses or amoxicillin 500mg PO every 8 hours) is recommended if the organism is susceptible 2, 3

Treatment Options for Complicated UTI

• Linezolid 600mg IV or PO every 12 hours is recommended for enterococcal infections, with treatment duration dependent on the site of infection and clinical response 2, 4
• High dose daptomycin 8-12 mg/kg IV daily (alone or in combination with β-lactams) is recommended for more serious enterococcal infections 2, 5
• Tigecycline 100mg IV loading dose followed by 50mg IV every 12 hours can be considered for complicated infections, particularly intra-abdominal infections with enterococcal involvement 2

Treatment Considerations Based on Resistance Pattern

For Vancomycin-Susceptible Enterococcus

• Ampicillin remains the drug of choice if the isolate is susceptible 1, 3
• For patients with penicillin allergy, nitrofurantoin or fosfomycin are appropriate alternatives 1

For Vancomycin-Resistant Enterococcus (VRE)

• Single dose fosfomycin 3g PO is recommended for uncomplicated UTIs 2, 3
• Nitrofurantoin 100mg PO every 6 hours is an effective option for lower UTIs 2, 3
• Linezolid has shown high cure rates (63%) specifically for VRE urinary tract infections 4, 6
• Daptomycin should be reserved for confirmed or suspected upper and/or bacteremic VRE UTIs 5, 6

Treatment Duration

• Uncomplicated lower UTI: 3-7 days of therapy is generally sufficient 1
• Complicated UTI: 7-14 days of therapy is recommended 1
• Male patients where prostatitis cannot be excluded: 14 days of therapy 2
• If the patient has been afebrile for at least 48 hours and is hemodynamically stable, a shorter duration may be appropriate 2

Special Considerations

• Catheter-associated UTIs: Consider catheter removal when possible, as this is a major risk factor for enterococcal UTIs 2, 5
• Antimicrobial resistance: Enterococci have shown increasing resistance to multiple antibiotics, making susceptibility testing crucial 3, 7
• Asymptomatic bacteriuria: Routine treatment is not recommended unless in high-risk populations (e.g., pregnant women, pre-urologic procedures) 1, 5
• Combination therapy: For serious infections, aminoglycosides may be considered as adjunctive therapy, though evidence is limited 5, 6

Common Pitfalls to Avoid

• Treating asymptomatic bacteriuria with enterococci can foster antimicrobial resistance 1, 5
• Using fluoroquinolones empirically is not recommended due to high resistance rates in enterococci 1, 3
• Prolonged therapy increases risk of resistance and adverse effects without additional benefit 1
• Failure to differentiate between colonization and true infection can lead to unnecessary antibiotic use 1, 3

Algorithm for Management

1. Confirm true infection (not just colonization) based on symptoms and urinalysis 1
2. Obtain urine culture and susceptibility testing before initiating therapy when possible 2, 3
3. Initiate empiric therapy based on local resistance patterns and patient factors 2
4. Adjust therapy once susceptibility results are available 2, 3
5. Consider catheter removal if present 2, 5
6. Determine appropriate duration based on infection complexity and clinical response 2, 1
7. Follow up with repeat cultures if symptoms persist despite appropriate therapy 1