Author Interviews, PLoS, Urinary Tract Infections / 18.12.2015
Complex Bacterial Biofilms Can Rapidly Obstruct Catheters
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.