What is the definition and treatment approach for Catheter-Associated Urinary Tract Infections (CAUTIs), including when to admit to hospital?

Definition and Management of Catheter-Associated Urinary Tract Infections (CAUTIs)

Catheter-associated urinary tract infection (CAUTI) refers to a UTI occurring in a person whose urinary tract is currently catheterized or has been catheterized within the past 48 hours, and is the leading cause of secondary healthcare-associated bacteremia. 1

Definition and Diagnosis

CAUTI Definition

• Signs and symptoms compatible with CAUTI include:
  • New onset or worsening fever
  • Rigors
  • Altered mental status
  • Malaise or lethargy with no other identified cause
  • Flank pain
  • Costovertebral angle tenderness
  • Acute hematuria
  • Pelvic discomfort
  • Dysuria, urgency, or frequent urination in patients whose catheter has been removed 1

Diagnostic Criteria

• Diagnosis requires both:
  • Urinalysis showing signs of infection (pyuria and/or bacteriuria)
  • Positive urine culture with ≥50,000 CFU/mL of a uropathogen 2
• Urine culture should be obtained prior to initiating antimicrobial therapy due to the wide spectrum of potential infecting organisms and increased likelihood of antimicrobial resistance 1

Microbiology

The microbial spectrum is broader than for uncomplicated UTIs, with higher antimicrobial resistance rates:

• Common pathogens include: E. coli, Proteus spp., Klebsiella spp., Pseudomonas spp., Serratia spp., and Enterococcus spp. 1
• Polymicrobial infections are common in patients with long-term catheterization 1

Treatment Approach

Initial Management

1. Replace the catheter if it has been in place for ≥2 weeks before starting antibiotics 1

   • This improves clinical outcomes and reduces polymicrobial bacteriuria
   • Obtain urine culture from the freshly placed catheter

2. Remove or discontinue the catheter as soon as possible 1

   • This is the most effective intervention to prevent complications

3. Initiate empiric antimicrobial therapy based on local resistance patterns and patient factors 1, 2

Empiric Antibiotic Recommendations

For patients with systemic symptoms (recommended by European Association of Urology): 1

• Use one of the following combinations:
  • Amoxicillin plus an aminoglycoside
  • A second-generation cephalosporin plus an aminoglycoside
  • An intravenous third-generation cephalosporin

Fluoroquinolone considerations: 1

• Only use ciprofloxacin if local resistance rate is <10% when:
  • The entire treatment is given orally
  • The patient does not require hospitalization
  • The patient has anaphylaxis to β-lactam antimicrobials
• Avoid ciprofloxacin and other fluoroquinolones for empirical treatment if:
  • Patient is from urology departments
  • Patient has used fluoroquinolones in the last 6 months

Treatment Duration

• 7-14 days is recommended for most patients with CAUTI, regardless of whether the catheter remains in place 1
• 5-day regimen with levofloxacin is likely sufficient for most patients with mild CAUTI 1
• 3-day regimen may be reasonable for younger women with mild CAUTI after catheter removal 1
• 14-day treatment for men when prostatitis cannot be excluded 1
• Shorter durations are preferred when appropriate to limit development of resistance 1

Adjusting Treatment

• Adjust regimen based on culture results and clinical course 1
• If no clinical response with defervescence by 72 hours, consider:
  • Extended treatment
  • Urologic evaluation 1

Prevention Strategies

Key Prevention Measures

1. Avoid unnecessary catheterization - most important preventive measure 1, 3
2. Remove catheters as soon as possible 1, 3
3. Use aseptic technique for catheter insertion 3
4. Implement reminder systems to prompt catheter removal 4
5. Establish infection control programs in healthcare settings 4

Institutional Recommendations

1. Develop and educate staff on appropriate indications for catheter insertion (target: 90% of catheters placed for appropriate indications) 1
2. Require physician's order before catheter placement (target: 95% compliance) 1
3. Consider use of hydrophilic-coated catheters for clean intermittent catheterization 4

When to Admit to Hospital

Admission criteria for patients with CAUTI:

• Sepsis (defined as life-threatening organ dysfunction from dysregulated host response to infection) 1
• Signs of systemic infection with hemodynamic instability
• Patients with complicating factors: 1
  • Vesicoureteral reflux
  • Immunosuppression
  • Recent history of instrumentation
  • ESBL-producing or multidrug-resistant organisms
• Inability to tolerate oral antibiotics
• Failure to respond to outpatient therapy

Common Pitfalls to Avoid

1. Do not screen for or treat catheter-associated asymptomatic bacteriuria (CA-ASB) in patients with short-term or long-term indwelling urethral catheters 1

   • Exception: Consider treatment of CA-ASB that persists 48 hours after short-term catheter removal in women to reduce subsequent CAUTI risk 1

2. Do not use prophylactic antimicrobials at the time of:

   • Catheter placement
   • Catheter removal
   • Catheter replacement 1

3. Do not use moxifloxacin for UTI treatment due to uncertainty regarding effective urine concentrations 1

4. Avoid routine periodic catheter changes to prevent bacteriuria or obstruction, as this practice is not evidence-based 1

5. Do not obtain follow-up urine cultures if symptoms resolve completely 2

By following these evidence-based guidelines for diagnosis, treatment, and prevention of CAUTIs, clinicians can optimize patient outcomes while practicing appropriate antimicrobial stewardship.