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Updated: Aug 4, 2026
Biomimetic Materials to Characterize Bacteria-host Interactions
Published on: November 16, 2015
Observations on the adherence of Proteus mirabilis onto polymer surfaces
D J Stickler1, J C Lear, N S Morris
1Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, UK. stickler@cardiff.ac.uk
Aims:
Infection of the catheterized urinary tract with Proteus mirabilis causes blockage of the catheter by crystalline bacterial biofilms. The aim of this work is to identify a surface-coating for catheters that is not vulnerable to colonization by Pr. mirabilis.
Methods And Results:
A parallel-plate flow-cell and phase contrast microscopy were used to follow bacterial adhesion onto polymer films. Experiments with a urease-negative mutant of Pr. mirabilis suspended in buffer or urine, identified agarose as a polymer on which biofilm did not form. In tests with wild-type urease-producing cells in urine, no adhesion of cells onto agarose was observed for 3 h but then as the pH rose above 8.2, the surface rapidly became colonized by crystalline biofilm.
Conclusions:
In urine at pH below 8.0, Pr. mirabilis does not adhere to agarose-coated surfaces. When the pH rises above 8.2, however, aggregates of crystals and bacteria form in the urine and are deposited on such surfaces.
Significance And Impact Of The Study:
Strategies to prevent the formation of crystalline biofilms on urinary catheters will need to consider both the properties of the surface-coatings and the requirement to prevent the alkaline conditions that induce crystal formation in urine.
Insights
Agarose coating prevents Proteus mirabilis biofilm formation on urinary catheters in urine below pH 8.0. However, alkaline conditions (pH > 8.2) promote crystal and biofilm deposition, necessitating strategies that also prevent pH increase.
Area of Science:
- Microbiology
- Biomaterials Science
- Urology
Background:
- Proteus mirabilis infection in catheterized urinary tracts leads to catheter blockage by crystalline bacterial biofilms.
- Developing effective anti-biofilm surface coatings for urinary catheters is crucial for patient care.
Purpose of the Study:
- To identify a catheter surface coating resistant to Proteus mirabilis colonization.
- To understand the conditions under which Proteus mirabilis forms biofilms on potential catheter surfaces.
Main Methods:
- Utilized a parallel-plate flow-cell and phase contrast microscopy to observe bacterial adhesion on polymer films.
- Tested adhesion of urease-negative and wild-type Proteus mirabilis strains in buffer and urine at varying pH levels.
Main Results:
- Agarose was identified as a polymer that prevented biofilm formation by urease-negative Proteus mirabilis.
- Wild-type Proteus mirabilis showed no initial adhesion to agarose in urine, but rapid crystalline biofilm formation occurred as urine pH rose above 8.2.
- Biofilm formation on agarose was inhibited in urine with pH below 8.0.
Conclusions:
- Agarose-coated surfaces resist Proteus mirabilis adhesion in urine at pH below 8.0.
- Alkaline conditions (pH > 8.2) in urine promote the formation of crystalline aggregates and subsequent biofilm deposition on surfaces.
- Preventing crystalline biofilm formation on catheters requires considering both surface properties and methods to avoid urine alkalinization.
