[35] Simple physical model to study formation and physiology of biofilms on urethral catheters

Stickler, D.J.; Morris, Nicola; Winters, C.

doi:10.1016/s0076-6879(99)10037-5

Cited by 98 publications

(90 citation statements)

References 13 publications

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“…Another CAUTI-based model attempted to simulate the bladder environment by growing polymicrobial biofilms in sterile AUM encased in a water jacket, and to develop catheter encrustation from mineral deposits from the urinary tract infection environment [70,71]. Proteus mirabilis, in conjunction with other CAUTI-relevant pathogens, were tested for their ability to form crystalline bacterial biofilms in the lumen of the catheter.…”

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confidence: 99%

Biofilm Models of Polymicrobial Infection

2015

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Interactions between microbes are complex and play an important role in the pathogenesis of infections. These interactions can range from fierce competition for nutrients and niches to highly evolved cooperative mechanisms between different species that support their mutual growth. An increasing appreciation for these interactions, and desire to uncover the mechanisms that govern them, has resulted in a shift from monomicrobial to polymicrobial biofilm studies in different disease models. Here we provide an overview of biofilm models used to study select polymicrobial infections and highlight the impact that the interactions between microbes within these biofilms have on disease progression. Notable recent advances in the development of polymicrobial biofilm-associated infection models and challenges facing the study of polymicrobial biofilms are addressed. Polymicrobial interactions in biofilmsOver the past 2 decades there has been a revolutionary paradigm shift in the field of microbiology with the appreciation that bacteria present in most biological systems exist in biofilms, rather than in a free-living state. This understanding has dramatically changed the way we study bacteria in the laboratory and resulted in the development of many new experimental systems that replicate biofilm environments [1][2][3][4][5]. Studies utilizing these systems have demonstrated time and time again that bacteria behave very differently when in a biofilm than during planktonic growth. In many ways, we now have to relearn everything we thought we knew about bacterial behavior through the view of the biofilm lens.Similarly, the recent explosion of metagenomic studies has significantly increased our appreciation of the complexity of the microbial populations present in biofilms [6,7]. This is also true for infections, most of which are thought to be biofilm related and inherently polymicrobial, including various species of bacteria, fungi and viruses [8]. It is thought that microbes act in concert to establish biofilms, which in turn can increase tolerance to antimicrobials, exacerbate of the host's immune response and increase persistence at the infection site [7,[9][10][11].Genetic diversity of microbes within biofilm communities is thought to increase the fitness of the residing community, making them more equipped to survive environmental stresses. In large part, this is due to an expanded gene pool, which can be more easily shared within the confines of a biofilm community [12]. Community composition and interactions within the community can have huge influences on bacterial behavior. Thus, just as the behavior of planktonic versus biofilm-associated bacteria is dramatically different, so is that of bacteria in single species versus multispecies systems.Interactions between microbes are complex and highly dependent on context. They can range from fierce competition for nutrients and niches, manifested by antagonistic behavior, to highly evolved cooperative mechanisms between different species that support their mutual grow...

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confidence: 99%

Biofilm Models of Polymicrobial Infection

2015

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“…The mixture was spread over a glass plate to allow the polymer mixture to set. Strips (2 cm long by 1 cm wide by 1 mm thick) of the calcium acetate-BTB polymer were then prepared, washed in water to remove residual acid, and stored at 4°C.The bladder model has been described previously (14). It consists of a glass chamber maintained at 37°C by a water jacket.…”

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confidence: 99%

“…The bladder model has been described previously (14). It consists of a glass chamber maintained at 37°C by a water jacket.…”

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confidence: 99%

A Sensor To Detect the Early Stages in the Development of CrystallineProteus mirabilisBiofilm on Indwelling Bladder Catheters

et al. 2006

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A simple sensor has been developed to detect the early stages of urinary catheter encrustation and avoid the clinical crises induced by catheter blockage. In laboratory models of colonization by Proteus mirabilis, the sensor signaled encrustation at an average time of 43 h before catheters were blocked with crystalline biofilm.The care of many elderly and disabled patients undergoing long-term bladder catheterization is complicated by the encrustation and blockage of their catheters (3, 15). The problem is unpredictable and can result in emergency referrals of patients with urinary retention or incontinence owing to catheter obstruction (5). The main cause of catheter encrustation is infection by urease-producing organisms, particularly Proteus mirabilis (6, 7). These organisms colonize the catheter, forming a biofilm (11, 13). The bacterial urease generates ammonia from urea, and the urine becomes alkaline. Under these conditions, crystals of calcium and magnesium phosphate are formed and a crystalline biofilm develops, which eventually blocks the flow of urine from the bladder (1, 2, 8).Our aim was to develop a simple sensor to signal an early warning of impending catheter encrustation and blockage. The idea was to produce sensors by impregnating polymeric materials with pH indicators. The sensors, located in the catheter drainage system, continuously monitor the pH at the surface of the catheter over a 7-day period (the interval after which the urine drainage bags are usually replaced). Bromothymol blue (BTB) was chosen as the indicator because of its transition from yellow to dark blue over the pH range 6 to 8. A change from an acid to an alkaline reaction at the sensor surface signals infection and biofilm formation by P. mirabilis. The appearance of the signal indicates that action should be taken to avoid an acute clinical episode. Our objectives were to (i) develop polymers suitable for the manufacture of sensors, (ii) test their ability to signal catheter encrustation in laboratory models, and (iii) identify the optimum location for the sensor in the drainage system. The sensors were prepared by dissolving cellulose acetate (Acordis Ltd., Coventry, United Kingdom) in acetone and adding a mixture of BTB (Sigma-Aldrich, St. Louis, Mo.) and sulfuric acid. Under these conditions, the BTB becomes covalently bound to the cellulose acetate. Polyethylene glycol was added as a plasticizer and to control the rate of movement of ions through the matrix, thus controlling the response rate of the material to changes in pH. The mixture was spread over a glass plate to allow the polymer mixture to set. Strips (2 cm long by 1 cm wide by 1 mm thick) of the calcium acetate-BTB polymer were then prepared, washed in water to remove residual acid, and stored at 4°C.The bladder model has been described previously (14). It consists of a glass chamber maintained at 37°C by a water jacket. Each model was sterilized by autoclaving, and then a 4.7-mm all-silicone catheter (Bard Ltd., Crawley, United Kingdom) was inserted into the...

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“…In 1997, the University of Massachusetts Medical Center introduced silver-hydrogel urinary catheters as a mean to reduce the incidence of catheter-associated UTIs; however, this reduction did not reach statistical significance [33]. The hydrogel coating provides the catheter with the important advantage of low static and kinetic friction factors [23], which are of key importance to patient care.…”

Section: Discussionmentioning

confidence: 99%

“…Artificial urine (AU) was adapted in-house upon the original work of Stickler et al [23]. The final constitution of the stock media was as follows, for 100 mL total volume: 2.3 g sodium disulphate, 0.65 g magnesium chloride, 4.6 g trisodium citrate, 0.02 g sodium oxalate, 2.8 g potassium dihydrogen orthophosphate, 1.6 g potassium chloride, 1 g ammonium chloride, 5 g gelatin, and 1 g tryptone soy broth.…”

Section: Artificial Urine Mediummentioning

confidence: 99%

The potential of photo-deposited silver coatings on Foley catheters to prevent urinary tract infections

Cooper

Pollini

Paladini

2016

Materials Science and Engineering: C

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Catheter-associated urinary tract infection (CAUTI) represents one of the most common causes of morbidity and mortality. The resistance demonstrated by many microorganisms to conventional antibiotic therapies and the in-creasing health-care costs have recently encouraged the definition of alternative preventive strategies, which can have a positive effect in the management of infections.Antimicrobial urinary catheters have been developed through the photo-chemical deposition of silver coatings on the external and luminal surfaces. The substrates are exposed to ultraviolet radiation after impregnation into a silver-based solution, thus inducing the in situ synthesis of silver particles. The effect of the surface treatment on the material was investigated through scanning electron microscopy (SEM) and silver ion release measurements. The ability of microorganisms commonly associated with urinary tract infections was investigated in terms of bacterial viability, proliferation and biofilm development, using Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis as target organisms. The silver coatings demonstrated good distribution of silver particles to the substrate, and proved an effective antibacterial capability in simulated biological conditions.The low values of silver ion release demonstrated the optimum adhesion of the coating. The results indicated a good potential of silver-based antimicrobial materials for prevention of catheterassociated urinary tract infection.

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[35] Simple physical model to study formation and physiology of biofilms on urethral catheters

Cited by 98 publications

References 13 publications

Biofilm Models of Polymicrobial Infection

Biofilm Models of Polymicrobial Infection

A Sensor To Detect the Early Stages in the Development of CrystallineProteus mirabilisBiofilm on Indwelling Bladder Catheters

The potential of photo-deposited silver coatings on Foley catheters to prevent urinary tract infections

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