What is a Catheter-Associated Urinary Tract Infection (CAUTI) and what is its current incidence in acute care settings?

Catheter-Associated Urinary Tract Infection (CAUTI): Definition and Incidence in Acute Care Settings

Catheter-Associated Urinary Tract Infection (CAUTI) is defined as a urinary tract infection that occurs in a patient who has had an indwelling urinary catheter in place for >2 days, with the infection occurring while the catheter is in place or within 48 hours after its removal, and it currently affects approximately 3-5% of catheterized patients per catheter day in acute care settings. 1

Definition and Diagnostic Criteria

A CAUTI is characterized by:

• Presence of an indwelling urinary catheter for >2 days
• Signs and symptoms of UTI (fever, suprapubic tenderness, costovertebral angle pain/tenderness)
• Positive urine culture with ≥10³ CFU/mL of bacterial species
• No other identified source of infection

It's important to distinguish CAUTI from catheter-associated asymptomatic bacteriuria (CA-ASB), which is the presence of bacteria in the urine without clinical symptoms of infection 2.

Current Incidence in Acute Care Settings

• CAUTIs account for approximately 40% of all healthcare-associated infections 3
• CAUTIs represent approximately 80% of all nosocomial urinary tract infections 3
• The incidence rate is approximately 3-5% per catheter day 1
• The risk of developing bacteriuria increases with duration of catheterization, with approximately 14.9% of newly catheterized patients developing bacteriuria at a mean of 6.4 days 2

Risk Factors for CAUTI

• Duration of catheterization (most significant risk factor) 2, 1
• Female gender
• Older age
• Diabetes mellitus
• Impaired immune system
• Poor catheter care
• Breaks in the closed drainage system
• Improper aseptic technique during insertion

Clinical Impact

• Only about 7.7% of patients with catheter-associated bacteriuria develop symptomatic UTI 2
• Approximately 0.5-0.7% of catheterized patients with bacteriuria develop bacteremia 2
• CAUTIs are associated with increased:
  • Hospital length of stay
  • Healthcare costs
  • Antimicrobial resistance
  • Risk of complications including pyelonephritis and sepsis

Prevention Strategies

The most effective prevention strategies include:

1. Limiting catheter use to strictly necessary indications 1
2. Early catheter removal as soon as medically possible 2, 1
3. Aseptic technique during catheter insertion 1
4. Proper catheter care including:
   • Hand hygiene
   • Maintaining a closed drainage system
   • Keeping the collection bag below bladder level
   • Regular perineal hygiene 1
5. Consider antimicrobial-coated catheters for short-term catheterization in high-risk patients 1

Common Pitfalls and Caveats

• Overtreating asymptomatic bacteriuria: Treatment of CA-ASB does not reduce symptomatic UTI episodes and leads to antimicrobial resistance 2, 1
• Inadequate specimen collection: Specimens should be collected after catheter replacement to avoid culturing biofilm organisms 1
• Failure to distinguish colonization from infection: Not all positive cultures represent true infection requiring treatment
• Prolonged catheterization: Catheters should be removed as soon as possible to reduce risk 2, 1

Management Approach

When CAUTI is suspected:

1. Obtain urine culture before starting antibiotics
2. Remove or change the indwelling catheter before collecting specimen and starting antibiotics 1
3. Reassess the need for continued catheterization
4. Select appropriate antimicrobial therapy based on local susceptibility patterns
5. Adjust therapy based on culture results
6. Monitor response to treatment within 72 hours 1

The high incidence of CAUTIs in acute care settings underscores the importance of prevention strategies focused on appropriate catheter use, early removal, and proper catheter care techniques.