Treatment for UTI Caused by Enterococcus faecalis in an 87-Year-Old Female with Impaired Renal Function
For an 87-year-old female with UTI caused by Enterococcus faecalis susceptible to tetracycline with eGFR 47, fosfomycin 3g as a single oral dose is the recommended first-line treatment due to its FDA approval for E. faecalis UTIs, good safety profile in renal impairment, and high urinary concentrations. 1
First-Line Treatment Options
- Fosfomycin 3g oral powder: Single dose treatment, FDA approved specifically for UTIs caused by E. faecalis, with good in vitro activity and promising results in observational studies 1
- Nitrofurantoin 100mg PO four times daily: FDA approved for lower UTIs with good activity against E. faecalis, but use with caution in elderly patients with eGFR 47 (relative contraindication if eGFR <45) 1, 2
- Ampicillin/Amoxicillin: If susceptibility is confirmed, ampicillin (IV) or amoxicillin 500mg PO every 8 hours can be effective, as ampicillin is considered the drug of choice for enterococcal infections 1
Treatment Considerations for Renal Impairment
- With eGFR 47, dose adjustments may be necessary for certain antibiotics 1
- Fosfomycin requires no dose adjustment in renal impairment, making it particularly suitable for this patient 2
- Nitrofurantoin should be used with caution as it's relatively contraindicated in patients with eGFR <45 ml/min 2, 3
- Tetracycline (since the organism is susceptible): Doxycycline 100mg twice daily can be considered, but is not a first-line agent for UTIs despite susceptibility 1, 3
Duration of Therapy
- For uncomplicated lower UTI: 3-7 days of therapy is generally sufficient 1
- For complicated UTI (considering patient's age and renal impairment): 7 days of therapy is recommended 1
- If the patient has been afebrile for at least 48 hours and is hemodynamically stable, a shorter duration may be appropriate 1
Alternative Options if First-Line Treatments Fail
- Linezolid 600mg IV/PO every 12 hours: Effective against resistant enterococci but should be reserved for more severe infections due to cost and side effect profile 1
- Daptomycin 6-12mg/kg IV daily: Consider for complicated UTIs if other options fail, but primarily for more serious infections 1
- Combination therapy: For severe or resistant infections, combinations such as ampicillin with an aminoglycoside may be considered, but use aminoglycosides with caution in renal impairment 1, 4
Important Clinical Considerations
- Differentiate between colonization and true infection before initiating therapy 1
- Obtain follow-up urine cultures if symptoms persist despite appropriate therapy 1
- Avoid unnecessary prolonged use of broad-spectrum antibiotics to prevent resistance development 1, 5
- Consider removing indwelling catheters if present, as catheterization is a major risk factor for UTIs 1, 4
Common Pitfalls to Avoid
- Treating asymptomatic bacteriuria: This can foster antimicrobial resistance and increase recurrent UTI episodes 1
- Using fluoroquinolones empirically: High resistance rates in enterococci (47% resistance to ciprofloxacin reported in some studies) make these suboptimal choices 6, 3
- Prolonged therapy: Unnecessarily long courses of antibiotics increase risk of resistance and adverse effects 1
- Ignoring susceptibility testing: Always tailor therapy based on culture results rather than continuing empiric therapy 1, 5