The effect of urease inhibitors on the encrustation of urethral catheters.
Encrustation and blockage of indwelling urethral catheters is primarily brought about by infection of the urinary tract by Proteus mirabilis or other urease-producing species. The bacteria colonise the catheter forming a biofilm community within a polysaccharide matrix. The activity of the urease drives up the urinary pH and causes the crystallisation of calcium and magnesium phosphates in the biofilm. We have used a simple physical model of the catheterised bladder to investigate the ability of urease inhibitors to control encrustation. It was observed that acetohydroxamic acid (1.0 mg/ml) and fluorofamide (1.0 microg/ml) restricted the increase in pH of P. mirabilis-infected urine from 9.1 to 7.6. Significant reductions in the deposition of calcium and magnesium salts were also recorded on the silicone catheters. Electron microscopy confirmed that encrustation and occlusion of the catheter lumen was minimal in the presence of the urease inhibitors. The data from this in vitro study suggests that urease inhibitors, particularly fluorofamide, could have clinical applications in the prevention of catheter encrustation and blockage.
School of Pure and Applied Biology, University of Wales Cardiff, UK.
N S
NS
Morris
D J
DJ
Stickler
D001549:Benzamides / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D003460:Crystallization; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D011513:Proteus mirabilis / Q000187:drug effects* / Q000502:physiology; D012828:Silicones; D014510:Urease / Q000037:antagonists & inhibitors*; D014546:Urinary Catheterization / Q000009:adverse effects* / Q000295:instrumentation; D014552:Urinary Tract Infections / Q000209:etiology / Q000517:prevention & control
D001549:Benzamides; D004791:Enzyme Inhibitors; D006877:Hydroxamic Acids; D012828:Silicones; C006358:acetohydroxamic acid; C032764:flurofamide; D014510:Urease