Studies on the formation of crystalline bacterial biofilms on urethral catheters

Stickler, D.J.; Morris, Nicola; Moreno, Mar; Sabbuba, N.

doi:10.1007/bf01708349

Cited by 49 publications

(36 citation statements)

References 11 publications

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“…Electron microscopy has been used for the examination and characterization of biofilms on medical devices (160,187) and in human infections (66,147). Because of its excellent resolution properties, the electron microscope will, in spite of its limitations, continue to be an important tool for the biofilm scientist.…”

Section: Biofilm Examination and Measurementmentioning

confidence: 99%

Biofilms: Survival Mechanisms of Clinically Relevant Microorganisms

2002

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Though biofilms were first described by Antonie van Leeuwenhoek, the theory describing the biofilm process was not developed until 1978. We now understand that biofilms are universal, occurring in aquatic and industrial water systems as well as a large number of environments and medical devices relevant for public health. Using tools such as the scanning electron microscope and, more recently, the confocal laser scanning microscope, biofilm researchers now understand that biofilms are not unstructured, homogeneous deposits of cells and accumulated slime, but complex communities of surface-associated cells enclosed in a polymer matrix containing open water channels. Further studies have shown that the biofilm phenotype can be described in terms of the genes expressed by biofilm-associated cells. Microorganisms growing in a biofilm are highly resistant to antimicrobial agents by one or more mechanisms. Biofilm-associated microorganisms have been shown to be associated with several human diseases, such as native valve endocarditis and cystic fibrosis, and to colonize a wide variety of medical devices. Though epidemiologic evidence points to biofilms as a source of several infectious diseases, the exact mechanisms by which biofilm-associated microorganisms elicit disease are poorly understood. Detachment of cells or cell aggregates, production of endotoxin, increased resistance to the host immune system, and provision of a niche for the generation of resistant organisms are all biofilm processes which could initiate the disease process. Effective strategies to prevent or control biofilms on medical devices must take into consideration the unique and tenacious nature of biofilms. Current intervention strategies are designed to prevent initial device colonization, minimize microbial cell attachment to the device, penetrate the biofilm matrix and kill the associated cells, or remove the device from the patient. In the future, treatments may be based on inhibition of genes involved in cell attachment and biofilm formation

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Section: Biofilm Examination and Measurementmentioning

confidence: 99%

Biofilms: Survival Mechanisms of Clinically Relevant Microorganisms

2002

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“…Stone formation makes P. mirabilis important in complicated UTIs, especially since P. mirabilis infections appear preferentially localized to the kidneys (Johnson et al, 1993b). Stickler and his collaborators (McLean et al, 1997 ;Stickler & Hughes, 1999 ;Stickler et al, 1998) The GenBank accession number for the sequence reported in this paper is AY044337.…”

Section: Introductionmentioning

confidence: 98%

Detection and mutation of a luxS-encoded autoinducer in Proteus mirabilis The GenBank accession number for the sequence reported in this paper is AY044337.

et al. 2002

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Quorum sensing regulates the expression of virulence factors in a wide variety of pathogenic bacteria. This study has shown that Proteus mirabilis harbours a homologue of luxS, a gene required for the synthesis of the quorum sensing autoinducer 2 (AI-2). AI-2 activity is expressed during and is correlated with the initiation of swarming migration on agar surfaces. The P. mirabilis luxS locus was cloned and a LuxS N strain constructed by allelic-exchange mutagenesis. While lacking AI-2 activity, a null mutation in luxS, however, did not affect swimming or swarming motility, swarmer cell differentiation, or virulence in a mouse model of ascending urinary tract infection.

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“…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.…”

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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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Studies on the formation of crystalline bacterial biofilms on urethral catheters

Cited by 49 publications

References 11 publications

Biofilms: Survival Mechanisms of Clinically Relevant Microorganisms

Biofilms: Survival Mechanisms of Clinically Relevant Microorganisms

Detection and mutation of a luxS-encoded autoinducer in Proteus mirabilis The GenBank accession number for the sequence reported in this paper is AY044337.

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

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