Complex Bacterial Biofilms Can Rapidly Obstruct Catheters

Dr Sandra A. Wilks PhD Senior Research Fellow IfLS Knowledge Mobilisation Fellow in Healthcare Technologies Faculty of Natural and Environmental Science & Faculty of Health Sciences Centre for Biological Sciences, University of Southampton, Southampton, UK

Dr. Sandra Wilks

MedicalResearch.com Interview with:
Dr Sandra A. Wilks PhD

Senior Research Fellow
IfLS Knowledge Mobilisation Fellow in Healthcare Technologies
Faculty of Natural and Environmental Science & Faculty of Health Sciences
Centre for Biological Sciences,
University of Southampton,
Southampton, UK 

Medical Research: What is the background for this study? What are the main findings?
Dr. Wilks: The use of indwelling Foley urinary catheters for extended periods of time results in high risks of urinary tract infections (UTI) and catheter blockages. Blockages are often caused by the presence of Proteus mirabilis, a urease-producing bacterium which results in an increase of the urine pH and the development of crystalline biofilms. Biofilms develop when bacteria attach to a surface, forming a community structure, held together by extracellular polymeric substances (EPS). Once in a biofilm, bacteria exhibit high resistance to the action of antibiotics and are protected by other stress factors. The crystalline biofilms resulting from the presence of Proteus are highly complex environments and cause complete blockage of the catheter within days. Such blockages cause pain and trauma for patients, and result in high demands on healthcare resources.

In this study, we have used an advanced microscopy technique (episcopic differential interference contrast, EDIC microscopy developed by Best Scientific) to track the development of these crystalline encrustations on two commonly used catheter materials; silicone and hydrogel latex. We have identified four distinct stages to crystalline biofilm formation;

  • (1) an initial foundation layer (conditioning film) formed by individual ‘colonising’ P. mirabilis cells, which occurred in less than 1 hour;
  • (2) this was rapidly followed by a sheet-like microcrystalline material (after 24 hours) that covers this conditioning film;
  • (3) after 4 days exposure, large amounts of crystalline material was seen to extend out from the surface with;
  • (4) defined struvite crystals embedded within the structure and P. mirabilis visible throughout. This pattern was the same on both materials.

Medical Research: What should clinicians and patients take away from your report?

Dr. Wilks: This study has revealed new information about how catheters are colonised by P. mirabilis and the complexity of the crystalline biofilm. With initial colonization occurring in less than one hour, it emphasizes the need for the rapid control of Proteus and the development of effective anti-biofilm materials.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Wilks: There is a clear need for an improvement in the materials used for urinary catheters. We are working towards developing a material which is able to prevent bacterial attachment and subsequent biofilm formation. However, it is also essential that we fully understand how biofilms develop, as only then can we be sure of the properties needed for such a material. We are therefore using advance microscopy and microbiological techniques to aid our understanding of the microbial communities found on catheters.
Improved control and prevention strategies for biofilms on urinary catheters would ultimately improve the quality of life for many long-term catheter users, as well as reducing burden on healthcare providers.

Citation:

Sandra A. Wilks, Mandy J. Fader, C. William Keevil. Novel Insights into the Proteus mirabilis Crystalline Biofilm Using Real-Time Imaging.
PLOS ONE, 2015; 10 (10): e0141711 DOI: 10.1371/journal.pone.0141711
Dr Sandra A. Wilks PhD (2015). Complex Bacterial Biofilms Can Rapidly Obstruct Catheters 

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