What is the appropriate management of a catheter-associated urinary tract infection caused by Enterococcus faecalis?

Management of Catheter-Associated UTI Caused by Enterococcus faecalis

For catheter-associated urinary tract infection caused by Enterococcus faecalis, obtain urine culture before treatment, replace the catheter if it has been in place ≥2 weeks, and treat with ampicillin (or vancomycin if resistant) for 7 days if symptoms resolve promptly or 10-14 days if response is delayed. 1

Initial Diagnostic Steps

• Obtain urine culture and susceptibility testing before initiating antibiotics due to the wide spectrum of potential organisms and high likelihood of antimicrobial resistance in catheter-associated infections 1, 2
• If the catheter has been in place for ≥2 weeks at infection onset, obtain the culture specimen from a freshly placed catheter rather than the old one, as biofilm on the old catheter may not accurately reflect bladder infection status 1

Catheter Management

Replace the catheter before starting antibiotics if it has been in place for ≥2 weeks (some guidelines suggest ≥12 weeks, but the most recent evidence supports 2 weeks) 1, 3. This intervention:

• Hastens resolution of symptoms 1
• Reduces risk of subsequent bacteriuria and recurrent UTI 1
• Decreases polymicrobial bacteriuria 1
• Shortens time to clinical improvement (typically <72 hours) 1

Remove the catheter entirely as soon as clinically appropriate, as this is the single most effective intervention for treatment success 1, 2

Antibiotic Selection

For Ampicillin-Susceptible E. faecalis (98% of E. faecalis strains):

• Ampicillin is the drug of choice with cure rates of 73-92% 1, 3, 4
• Dosing: High-dose ampicillin 18-30 g IV daily in divided doses, or amoxicillin 500 mg every 8 hours for less severe infections 3

For Ampicillin-Resistant E. faecalis:

• Vancomycin is the alternative agent 1, 4

For Vancomycin-Resistant E. faecalis (rare in E. faecalis, only 2% of strains):

• Linezolid 600 mg every 12 hours achieves 67% cure rate in intention-to-treat populations and up to 91% in clinically evaluable patients 3
• Daptomycin may be used based on susceptibility results, though cure rates are lower (44% in neutropenic patients) 3

Treatment Duration

The treatment duration depends on clinical response:

• 7 days for uncomplicated CA-UTI with prompt symptom resolution (defervescence within 72 hours) 1, 3, 2
• 10-14 days for delayed clinical response (persistent fever or symptoms beyond 72 hours) 1, 3, 2
• 5 days of levofloxacin (750 mg daily) may be considered for non-severely ill patients, though this is less applicable for enterococcal infections given intrinsic resistance patterns 1
• 3 days may be sufficient for women ≤65 years who develop CA-UTI without upper tract symptoms after catheter removal 1

These durations apply regardless of whether the catheter remains in place or is removed 1

Special Considerations and Monitoring

Evaluate for Complications:

Obtain transesophageal echocardiography (TEE) if any of the following are present: 3, 4

• New cardiac murmur or embolic phenomena
• Persistent bacteremia or fever >72 hours despite appropriate antibiotics
• Radiographic evidence of septic pulmonary emboli
• Presence of prosthetic valve or other endovascular devices

The risk of endocarditis with enterococcal CA-UTI is relatively low (1.5% in one large series), but enterococcal bacteremia persisting >4 days is independently associated with increased mortality 1, 3

Follow-up Blood Cultures:

• Obtain follow-up blood cultures at 72 hours after starting appropriate antibiotics if bacteremia was present 4
• If blood cultures remain positive >72 hours, this indicates treatment failure and requires catheter removal if still in place 4

Combination Therapy:

The role of combination therapy (cell wall-active antibiotic plus aminoglycoside) for enterococcal CA-UTI without endocarditis remains unresolved 1. However:

• One large series found combination therapy with gentamicin and ampicillin was more effective than monotherapy when attempting catheter salvage 1, 3
• Consider combination therapy only if the catheter must be retained for compelling reasons 4

Common Pitfalls to Avoid

• Do not treat asymptomatic bacteriuria in catheterized patients, as this promotes antimicrobial resistance without clinical benefit 1, 2
• Do not use fluoroquinolones empirically for enterococcal infections, as E. faecalis has intrinsic resistance to fluoroquinolones 2
• Do not use moxifloxacin for UTI treatment due to uncertainty regarding effective urinary concentrations 1
• Do not delay catheter replacement in long-term catheterized patients (≥2 weeks), as this significantly impairs treatment response 1
• Do not assume clinical response by 24-48 hours; enterococcal infections may require up to 72 hours for defervescence even with appropriate therapy 1

Risk Factors for E. faecalis CA-UTI

In older patients with complicated community-acquired UTI, E. faecalis should be suspected and covered empirically if: 5

• Indwelling urinary catheter is present (OR 2.05)
• Previous urinary instrumentation (OR 2.16)
• Male sex and advanced age (mean 82 years)
• Multiple comorbidities

These patients have inadequate empirical antimicrobial therapy rates of 66.6% when E. faecalis is not covered, compared to 19% for Gram-negative UTI 5

Algorithm Summary

1. Obtain urine culture before antibiotics 1, 2
2. Replace catheter if in place ≥2 weeks; obtain culture from fresh catheter 1, 3
3. Start ampicillin (or vancomycin if resistant) based on local resistance patterns 1, 4
4. Treat for 7 days if prompt response, 10-14 days if delayed 1, 3
5. Obtain TEE if signs of endocarditis or persistent bacteremia >72 hours 3, 4
6. Remove catheter entirely as soon as clinically feasible 1, 2