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Raster-electron-microscopic investigations in large-bore catheters for extracorporeal detoxification
R Bambauer1, P Mestres, K J Piroung
1Department of Nephrology and Anatomy, University of Saarland, Homburg/Saar, F.R.G.
Abstract:
Large bore catheters (n = 42, 31 patients) which remained in position for a period of between 2 to 73 days (mean = 26.8 days/patients) were investigated with raster electron-microscopy (scanning electron micrographic: SEM) and for bacterial colonisation. Microbiological findings indicated colonisation of the intravascular large bore catheters in 8 out of 42 catheters (19%). SEM morphological investigation showed bacterial colonisation in only 3 catheters (7%). The 3 different catheter materials had small deposits of fibrin and protein on the inner and outer surfaces after 2 days. This second layer covered the entire surface after 3 days and increased to a thickness of 3-60 microns in the following days. In this matrix erythrocytes, thrombocytes and granulocytes could also been seen.
Insights
Scanning electron microscopy revealed bacterial colonization on only 7% of large bore catheters. Protein and fibrin deposits formed a biofilm matrix on catheter surfaces within days, trapping blood cells.
Area of Science:
- Medical Devices
- Microbiology
- Biomaterials
Background:
- Large bore catheters are essential in patient care but prone to complications.
- Catheter colonization by bacteria can lead to serious infections.
- Understanding biofilm formation on catheter surfaces is crucial for infection prevention.
Purpose of the Study:
- To investigate bacterial colonization on large bore catheters.
- To examine the surface morphology and biofilm development using scanning electron microscopy (SEM).
Main Methods:
- Analysis of 42 large bore catheters (31 patients) using SEM.
- Microbiological assessment for bacterial presence.
- Morphological examination of catheter surfaces over time.
Main Results:
- Bacterial colonization detected in 19% of catheters microbiologically.
- SEM confirmed bacterial colonization in only 7% of catheters.
- Fibrin and protein deposits formed a biofilm within 3 days, increasing in thickness.
- Erythrocytes, thrombocytes, and granulocytes were observed within the biofilm matrix.
Conclusions:
- SEM offers a detailed view of catheter surface changes.
- Biofilm formation on large bore catheters occurs rapidly, involving host-derived materials.
- Discrepancies between microbiological and SEM findings warrant further investigation into detection methods.