The development of crystalline Proteus mirabilis biofilms on Foley catheters

Abstract number: 1134_03_422

Morgan S.D., Stickler D.J.


The management of many patients undergoing long-term bladder catheterisation is complicated by the encrustation and blockage of their catheters. The problems result from infection by urease producing bacteria. The organisms colonize the catheters, the urease induces alkaline conditions under which calcium and magnesium phosphates precipitate and the resulting crystalline biofilm blocks the flow of urine. The aim of this study was to investigate the early stages of biofilm formation on a range of catheter types.


A laboratory model of the catheterised bladder was supplied with urine and infected with Proteus mirabilis NSM6, a clinical isolate from an encrusted catheter. Models were fitted with five different types of catheters. After incubation for various periods up until the times they blocked, catheters were removed from the models for examination. Scanning electron microscopy and X-ray microanalysis were used to follow the colonization of catheters by bacteria and crystalline material.


All-silicone, hydrogel-coated latex and silicone-coated latex catheters all acquired a layer of crystalline material within 4 h. These deposits consisted predominantly of calcium phosphate. Subsequently, they become colonized by large numbers of bacilli and the rapidly developing crystalline biofilm blocked the catheters within 12.5 h–42.5 h. In the case of a nitrofurazone- impregnated all-silicone catheter, although the initial process was slower, with the crystalline layers being first observed at 12 h, catheter blockage occurred at 29 h. Triclosan-impregnated silicone catheters however, showed little sign of encrustation or biofilm formation and were still draining urine freely at 7 days when the experiment was terminated.


The catheters currently available for long-term bladder management were rapidly colonized by crystalline P. mirabilis biofilm. Triclosan-impregnated catheters however were able to resist encrustation and biofilm formation in vitro for up to 7 days.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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