What is CAUTI (Catheter-Associated Urinary Tract Infection)?

Catheter-Associated Urinary Tract Infection (CAUTI)

CAUTI is a urinary tract infection that occurs in patients with indwelling urinary catheters and represents the most common healthcare-associated infection, accounting for approximately 70-80% of all hospital-acquired urinary tract infections, with significant impacts on patient morbidity, mortality, and healthcare costs. 1, 2

Definition and Epidemiology

• CAUTIs develop when bacteria enter the urinary tract via the catheter, forming biofilms on the inner and outer surfaces of the catheter 1
• The International Nosocomial Infection Control Consortium reports higher CAUTI rates in low- and middle-income countries (gradually reducing from 8.9 to 2.91 per 1000 catheter-days) compared to high-income countries like the US (median rate of 1.3 per 1000 catheter-days) 1
• CAUTIs account for almost half of all hospital-acquired infections 3
• Each CAUTI case costs approximately $1006 in the United States 1

Causative Organisms

• Predominant pathogens include:
  • Enteric Gram-negative bacilli (E. coli, Klebsiella, Proteus)
  • Enterococci
  • Pseudomonas aeruginosa
  • Candida species 2, 4
• Multidrug resistance is increasingly common among urinary pathogens 4

Risk Factors

The most significant risk factors for developing CAUTI include:

• Duration of catheterization (most important risk factor) 1, 4, 5
• Female sex
• Older age
• Immunocompromised status (oncology patients, AIDS patients, transplant recipients)
• Comorbidities such as diabetes mellitus, hypertension, cerebrovascular disease
• Spinal cord lesions and neurogenic bladder 2

Diagnosis

Diagnosis of CAUTI can be challenging, particularly distinguishing between asymptomatic bacteriuria and symptomatic infection:

• Key diagnostic criteria:

  • Presence of urinary catheter for >2 days
  • Signs/symptoms of UTI (fever, suprapubic tenderness, costovertebral angle pain)
  • Pyuria (≥10 WBCs/high-power field) or positive leukocyte esterase/nitrite test
  • Positive urine culture (>10³ CFU/mL of uropathogens) 2

• Important diagnostic practices:

  • Remove and replace the catheter before collecting specimens
  • Obtain urinalysis for leukocyte esterase and nitrite
  • Perform microscopic examination for WBCs
  • Culture and susceptibility testing is essential before starting antibiotics 2

Treatment

• Asymptomatic bacteriuria should not be treated with antibiotics (A-I level recommendation) 2

• For symptomatic CAUTI:

  1. Remove or replace the catheter if possible
  2. Obtain urine culture before starting antibiotics
  3. Select empiric antibiotics based on local susceptibility patterns:
     • For uncomplicated UTIs: nitrofurantoin, fosfomycin, or trimethoprim-sulfamethoxazole
     • For complicated UTIs: ceftazidime-avibactam, meropenem-vaborbactam, or imipenem-cilastatin-relebactam 2
  4. Adjust therapy based on culture results
  5. Monitor clinical response within 72 hours 2

• Special populations requiring lower threshold for hospitalization and IV antibiotics:

  • Pregnant women
  • Diabetics
  • Immunocompromised patients 2

Prevention Strategies

Prevention is critical and should focus on:

1. Avoid unnecessary catheterization - strictly limit to appropriate indications 2, 5
2. Minimize duration of catheterization - remove catheters as soon as medically possible with daily assessment of necessity 2, 5
3. Use proper insertion technique - aseptic technique during catheter placement 2, 5
4. Maintain proper catheter care:
   • Hand hygiene before and after handling catheters
   • Maintain closed drainage system
   • Keep collection bag below bladder level
   • Regular perineal hygiene 2
5. Consider antimicrobial-coated catheters for short-term catheterization 2
6. Patient education on proper catheter care, hand hygiene, and adequate hydration 2

Common Pitfalls and Caveats

• Avoid treating asymptomatic bacteriuria - this is common in catheterized patients but should not be treated with antibiotics 2
• Avoid routine catheter changes - insufficient evidence supports routine periodic catheter changes to prevent CAUTI 1
• Avoid prophylactic antimicrobials at catheter placement, removal, or replacement 1
• Avoid disconnection and reconnection of drainage systems as this increases infection risk 2
• Do not use urine cultures without signs/symptoms of infection as a basis for treatment 2

Complications

CAUTIs are associated with significant complications:

• Increased mortality
• Extended hospital length of stay
• Higher healthcare costs
• Antimicrobial resistance
• Risk of progression to pyelonephritis and sepsis 2

Implementing comprehensive prevention strategies has been shown to decrease both urinary catheter use and CAUTI rates, ultimately improving patient outcomes and reducing healthcare costs 1, 5.