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Scanning electron microscopy of bacterial biofilms on indwelling bladder catheters
L Ganderton1, J Chawla, C Winters
1School of Pure and Applied Biology, University of Wales College of Cardiff, UK.
Abstract:
Fifty Foley bladder catheters that had been indwelling for periods ranging from 3 to 83 days (mean 35 days) were examined for the presence of bacterial biofilm. Scanning electron microscopy on freeze-dried cross-sections and fixed, critical point-dried longitudinal sections revealed biofilm formation on the luminal surfaces of 44 of the catheters. Culture of urine samples and sonicates from catheters revealed that the prevalence of bacteriuria was less than that of catheter colonization. A wide range of nosocomial species were found colonizing the catheters, Escherichia coli being most often isolated. The bacterial composition of the biofilms ranged from single species to mixed communities containing up to four species. There was no relationship between the length of time that the catheter had been in situ and the extent of biofilm formation. The biofilms varied in thickness from 3 to 490 microns and were visible as layers of bacterial cells up to about 400 cells deep, embedded in a matrix.
Insights
Bacterial biofilm commonly forms on Foley bladder catheters, even early in use. This study found biofilm on 88% of catheters, regardless of indwelling duration, highlighting a significant issue in catheter-associated infections.
Area of Science:
- Microbiology
- Biomedical Engineering
- Infectious Diseases
Background:
- Urinary catheterization is a common medical procedure.
- Catheter-associated urinary tract infections (CAUTIs) are a significant healthcare concern.
- Bacterial biofilm formation on indwelling devices contributes to persistent infections.
Purpose of the Study:
- To investigate the prevalence and characteristics of bacterial biofilm on Foley bladder catheters.
- To compare catheter colonization with bacteriuria.
- To explore the relationship between indwelling time and biofilm formation.
Main Methods:
- Examination of 50 Foley bladder catheters indwelling for 3-83 days.
- Scanning electron microscopy (SEM) of catheter cross-sections and longitudinal sections.
- Bacterial culture of urine samples and catheter sonicates.
Main Results:
- Biofilm was detected on the luminal surfaces of 44 out of 50 (88%) catheters.
- Catheter colonization was more prevalent than bacteriuria.
- Nosocomial bacterial species, including Escherichia coli, were identified in biofilms.
- Biofilm thickness ranged from 3 to 490 microns.
- No correlation was found between indwelling duration and biofilm extent.
Conclusions:
- Bacterial biofilm formation is a common occurrence on indwelling Foley bladder catheters.
- Biofilm can form independently of the duration of catheterization.
- Understanding biofilm dynamics is crucial for preventing and managing catheter-associated infections.