Should nephrostomy tubes be replaced in a patient with bilateral nephrostomy tubes due to obstruction for chronic cystitis who develops a urinary tract infection (UTI)?

Management of UTI in a Patient with Bilateral Nephrostomy Tubes

In a patient with bilateral nephrostomy tubes who develops a urinary tract infection, the nephrostomy tubes should be replaced after obtaining appropriate cultures and before initiating antimicrobial therapy. 1, 2

Diagnostic Approach

1. Obtain cultures properly:

   • Change the nephrostomy catheter first
   • Collect urine specimen after allowing for urine accumulation
   • Never collect urine from extension tubing or collection bag 1

2. Obtain both:

   • Urinalysis (to confirm signs of infection)
   • Urine culture (≥50,000 CFU/mL of a uropathogen is diagnostic) 2

Treatment Algorithm

Step 1: Source Control

• Replace nephrostomy tubes if they have been in place for ≥2 weeks 2
• Tube exchange within 4 days of infection diagnosis significantly reduces recurrence risk (OR 0.1; p = 0.048) 3

Step 2: Antimicrobial Therapy

• Empiric therapy based on local resistance patterns and patient factors:

  • For systemic symptoms: amoxicillin plus aminoglycoside, second-generation cephalosporin plus aminoglycoside, or IV third-generation cephalosporin 2
  • For non-systemic symptoms: fluoroquinolones (if local resistance <10%), trimethoprim-sulfamethoxazole, or cephalosporins 1

• Duration:

  • 7-14 days for complicated UTIs 1, 2
  • 5 days with levofloxacin may be sufficient for mild cases 2

Step 3: Follow-up

• Adjust antibiotics based on culture results and clinical response
• If no clinical improvement within 72 hours, consider:
  • Upper tract imaging to evaluate for complications
  • Extended antimicrobial course
  • Urologic evaluation 2

Rationale and Evidence

Nephrostomy tube replacement is crucial because:

1. Biofilm formation: Bacteria adhere to catheter surfaces and form biofilms that protect them from antibiotics

2. Improved outcomes: Studies show that changing the catheter:

   • Reduces recurrent infections 3
   • Improves antibiotic efficacy
   • Provides accurate cultures for targeted therapy 2

3. Concordant antibiotic use after tube exchange significantly decreases recurrent infections (OR 0.04; p = 0.008) 3

Special Considerations

• Imaging: Consider upper tract imaging (ultrasound or CT) to evaluate for complications such as stones, hydronephrosis, or abscess formation 1

• Microbial spectrum: Expect broader spectrum of pathogens than uncomplicated UTIs, including:

  • E. coli
  • Proteus spp.
  • Klebsiella spp.
  • Pseudomonas spp.
  • Serratia spp.
  • Enterococcus spp. 1, 2

• Antimicrobial resistance: Higher likelihood in patients with indwelling catheters 1

Common Pitfalls to Avoid

1. Treating asymptomatic bacteriuria: Do not treat unless patient is symptomatic or prior to urologic procedures 1

2. Delaying tube exchange: Prompt replacement (within 4 days) significantly reduces recurrence risk 3

3. Using prophylactic antibiotics: Not recommended for routine nephrostomy tube changes in patients without active infection 4, 5

4. Inadequate cultures: Obtaining cultures from extension tubing or collection bags rather than fresh urine after tube change 1

5. Overlooking complications: Failing to consider upper tract imaging when appropriate 1