Blockage of urethral catheters by bacterial biofilms.

We report the case of a 63-year-old woman whose indwelling urethral catheter became blocked regularly at 4-5 day intervals over a period of 10 weeks. 'Worm-like' structures 25-30 cm in length were found either in the catheter, completely occluding the lumen, or in the drainage tube thereby blocking the valve of the drainage bag. Electron microscopy showed that these structures were composed of bacteria, while culture revealed them to be mixed communities of Pseudomonas aeruginosa, Escherichia coli, Enterococcus faecalis and Proteus mirabilis. Following treatment with ciprofloxacin, catheter drainage continued freely for a further period of 10 weeks.