Urinary pH and the Indwelling Catheter

Norberg, Astrid; Norberg, Bo; Lundbeck, Kari; Parkhede, Ulf

doi:10.3109/03009738009179181

Cited by 15 publications

(3 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Most of this rise occurs within a period of 2 h, and the pH remains approximately constant for the remaining seven days of the test. The final pH value is within the range of pH values of 6.5-10 which have been recorded for naturally infected urine in catheters (Norberg et al, 1980).…”

Section: Resultsmentioning

confidence: 99%

An Automated Technique for in Vitro Assessment of the Susceptibility of Urinary Catheter Materials to Encrustation

Cox

Hukins

Davies

et al. 1987

Engineering in Medicine

View full text Add to dashboard Cite

An automated technique has been developed for assessing the extent to which existing or potential materials for the construction of indwelling catheters become encrusted during exposure to infected urine. In this technique the enzyme urease is added to artificial urine containing albumin in a reaction vessel which contains the samples to be tested. Controlled replacement of reactants leads to appreciable formation of encrusting deposits which adhere firmly to the surface of the test samples. Deposits have the same chemical composition as those which encrust catheters in vivo.

show abstract

Section: Resultsmentioning

confidence: 99%

An Automated Technique for in Vitro Assessment of the Susceptibility of Urinary Catheter Materials to Encrustation

Cox

Hukins

Davies

et al. 1987

Engineering in Medicine

View full text Add to dashboard Cite

show abstract

“…The importance of urease-producing organisms in catheter encrustation, which may lead to obstruction, has been demonstrated by several groups. For example, Norberg et al (174) isolated Proteuts strains from 13 of 15 patients with catheters removed because of obstruction; however, the frequency of Protelus isolation was not reported for catheters removed for other reasons. Burns and Gauthier (29) demonstrated that catheter encrustation in five patients with long-term indwelling catheters could be significantly reduced by the administration of acetohydroxamic acid.…”

Section: Role Of Urease In Pathogenesismentioning

confidence: 99%

Microbial ureases: significance, regulation, and molecular characterization

1989

View full text Add to dashboard Cite

Microbial ureases hydrolyze urea to ammonia and carbon dioxide. Urease activity of an infectious microorganism can contribute to the development of urinary stones, pyelonephritis, gastric ulceration, and other diseases. In contrast to these harmful effects, urease activity of ruminal and gastrointestinal microorganisms can benefit both the microbe and host by recycling (thereby conserving) urea nitrogen. Microbial ureases also play an important role in utilization of environmental nitrogenous compounds and urea-based fertilizers. Urease is a high-molecular-weight, multimeric, nickel-containing enzyme. Its cytoplasmic location requires that urea enter the cell for utilization, and in some species energy-dependent urea uptake systems have been detected. Eucaryotic microorganisms possess a homopolymeric urease, analogous to the well-studied plant enzyme composed of six identical subunits. Gram-positive bacteria may also possess homopolymeric ureases, but the evidence for this is not conclusive. In contrast, ureases from gram-negative bacteria studied thus far clearly possess three distinct subunits with Mrs of 65,000 to 73,000 (alpha), 10,000 to 12,000 (beta), and 8,000 to 10,000 (gamma). Tightly bound nickel is present in all ureases and appears to participate in catalysis. Urease genes have been cloned from several species, and nickel-containing recombinant ureases have been characterized. Three structural genes are transcribed on a single messenger ribonucleic acid and translated in the order gamma, beta, and then alpha. In addition to these genes, several other peptides are encoded in the urease operon of some species. The roles for these other genes are not firmly established, but may involve regulation, urea transport, nickel transport, or nickel processing.

show abstract

“…Whether the sensor is measuring pHv or the pH of the biofilm is not certain, but the time between sensor indication and blockage would suggest that the relationship between pH and the encrustation process may be too complex or capricious for pHv to be a single proxy measure for impending blockage. Several studies have investigated the relationship between pHv, the presence of urease‐producing micro‐organisms and propensity for catheters to encrust . Hedelin et al.…”

Section: Discussionmentioning

confidence: 99%

A clinical evaluation of a sensor to detect blockage due to crystalline biofilm formation on indwelling urinary catheters

et al. 2014

View full text Add to dashboard Cite

ObjectiveTo test the performance and acceptability of an early warning sensor to predict encrustation and blockage of long-term indwelling urinary catheters. Patients and MethodsIn all, 17 long-term indwelling catheter users, 15 'blockers' and two 'non-blockers' (controls) were recruited; 11 participants were followed prospectively until catheter change, three withdrew early and three did not start.Two sensors were placed in series between the catheter and the urine bag at catheter change. The sensor nearest the bag was changed at the same time as the bag change (weekly); the sensor nearest the catheter remained in situ for the duration of the catheter's life.Bacteriology and pH determinations were performed on urine samples at each bag, sensor and catheter change. The colour of the sensors was recorded daily. On removal, each sensor and the catheter were examined for visible evidence of encrustation and blockage.Participants were asked to keep a daily diary to record colour change and any other relevant observations and to complete a psychosocial impact of assistive devices tool at the end of the study. Participants and carers/healthcare professionals (when involved in urine bag or catheter change) were asked to complete a questionnaire about the sensor. ResultsUrease-producing bacteria were isolated from seven of the 14 patients (including early withdrawals; P. mirabilis in four, Morganella or Providencia in three).In six of the seven patients the sensors turned blue-black; two of these were early withdrawals, two went to planned catheter change (one of these was recruited as a 'non-blocker') and three had catheter blockage.The number of days of catheterisation before blockage was 22, 23 and 25 days, and the sensor changed colour within 24-48 h after insertion.The urine mean (range) pH of the sensors that turned blue-black was 7.6 (5.5-9.0) and of the sensors that remained yellow 6.1 (5.1-7.5).The sensor was generally well-received and was positive in the psychosocial assessment. ConclusionsThe sensor is a useful indicator of urine pH and of the conditions that lead to catheter blockage.It may be particularly useful for new indwelling catheter users.To be a universally acceptable predictor of catheter blockage, the time from sensor colour change to blockage needs to be reduced.

show abstract

Urinary pH and the Indwelling Catheter

Cited by 15 publications

References 3 publications

An Automated Technique for in Vitro Assessment of the Susceptibility of Urinary Catheter Materials to Encrustation

An Automated Technique for in Vitro Assessment of the Susceptibility of Urinary Catheter Materials to Encrustation

Microbial ureases: significance, regulation, and molecular characterization

A clinical evaluation of a sensor to detect blockage due to crystalline biofilm formation on indwelling urinary catheters

Contact Info

Product

Resources

About