Related Experiment Videos
Catheter-associated urinary tract infections: epidemiology, pathogenesis, and prevention
1Department of Medicine, Harborview Medical Center, University of Washington, Seattle 98104.
Insights
Catheter-associated urinary tract infections (UTIs) are common hospital infections. Preventing bacterial entry and understanding risk factors like catheter duration and gender are key to future control strategies.
Area of Science:
- Urology
- Infectious Diseases
- Hospital Epidemiology
Background:
- Catheter-associated urinary tract infections (UTIs) are the most frequent nosocomial infections.
- UTIs can lead to bacteremia and increased mortality, with risk factors including catheter duration, female sex, and catheter-collecting tube disconnection.
- Bacteriuria in long-term catheterization is inevitable, with specific bacterial species causing encrustation and persistent infections.
Purpose of the Study:
- To review the epidemiology, risk factors, and prevention strategies for catheter-associated urinary tract infections.
- To highlight the challenges in controlling UTIs and identify future research directions.
Main Methods:
- Literature review of studies on catheter-associated urinary tract infections.
- Analysis of risk factors, bacterial pathogenesis, and prevention trials.
- Synthesis of current knowledge and identification of research gaps.
Main Results:
- Bacterial entry routes differ by gender (periurethral in women, intraluminal in men).
- Biofilm formation on catheters promotes encrustation and protects bacteria.
- Previous prevention efforts have had limited success; some interventions show efficacy in trials but require patient stratification by risk factors.
Conclusions:
- Effective UTIc prevention requires innovative catheter designs and targeted antimicrobial strategies.
- Further research into bacterial-host interactions and novel prophylaxis is crucial.
- Stratifying patients by risk factors like gender and catheter duration is essential for interpreting trial results.
Abstract:
Catheter-associated urinary tract infections (UTIc) remain the most common nosocomial infection. Although usually benign, UTIc cause bacteremia in 2-4% of patients and have been associated with a case fatality rate three times as high as nonbacteriuric patients. Risk factors for UTIc identified in multivariate analyses include increasing duration of use, female sex, absence of systemic antibiotics, and disconnection of the catheter-collecting tube junction. Recent studies suggest that most episodes of low colony count bacteriuria (10(2)-10(4) cfu/ml) rapidly progress to high (greater than or equal to 10(5)/ml) colony counts within 24-48 hours. In persons with long-term catheterization, bacteriuria inevitably develops and the infecting strains change frequently. In this setting, Proteus and Morganella species produce catheter encrustations and persistent bacteriuria. Routes of bacterial entry have been well defined and differ by gender, with the periurethral route predominating in women and the intraluminal route in men. Growth of bacteria in biofilms on the inner surface of catheters promotes encrustation and may protect bacteria from antimicrobial agents. Bacterial virulence factors have not been well characterized in UTIc, but fimbrial adhesins have been associated with bacterial persistence in the catheterized urinary tract, and urease production has been associated with stone formation and catheter encrustation. Recent efforts to prevent UTIc have focused mainly on preventing bacterial entry to the urinary tract or eradicating bacteriuria after its onset and have been largely unsuccessful. Systemic antimicrobials, sealed tubing and catheter junctions, silver ion-coated catheters, and antiseptics in the collecting bag have all been efficacious in one or more controlled trials. Failure to stratify patients by major risk factors, especially gender, antimicrobial exposure, and catheter duration, makes interpretation of many trials difficult. Further research in the areas of innovative catheter system design, bacterial-host epithelial cell interaction, and targeted antimicrobial prophylaxis seem the most likely approaches to controlling UTIc in the future.