Biofilm Formation in Indwelling Percutaneous Nephrostomy Catheters: Luminal Loss and Bacterial Colonization

Biofilm formation on the surface of percutaneous nephrostomy and percutaneous nephroureteral catheters is presumed to result in luminal narrowing and predispose to infection. This presumption drives clinical practice in varying ways. However, no study thus far has quantifiably characterized biofilm development in percutaneous nephrostomy/percutaneous nephroureteral catheters.

In this prospective study, removed percutaneous nephrostomy and percutaneous nephroureteral catheters were collected from patients undergoing catheter exchange. Catheters were stained with crystal violet and analyzed to assess biofilm deposition on the internal and external catheter surfaces and to quantify internal biofilm thickness. Pre- and post-exchange urine samples were collected from the catheters and analyzed for bacteria and leukocytes per high-power field.

A total of 38 catheters were collected (28 percutaneous nephrostomy, 10 percutaneous nephroureteral). Biofilm was present in all catheters and significantly increased with time. Luminal diameter loss due to biofilm (mean ± standard deviation) was 67 ± 17 μm at 0-2 weeks (n = 3), 104 ± 12 μm at 2-4 weeks (n = 4), 149 ± 32 μm at 1-2 months (n = 10), 236 ± 73 μm at 2-3 months (n = 11), 249 ± 39 μm at 3-4 months (n = 7), and 349 ± 8 μm at >6 months (n = 3). Catheter exchange resulted in a reduction in mean urine leukocytes (p = 0.0004) and bacteria per high-power field (p = 0.0061), but not complete elimination.

Biofilm forms on percutaneous nephrostomy/percutaneous nephroureteral catheters within a few days after placement and gradually progresses, occupying more than 200 μm of the luminal diameter by 2 months. Catheter exchange results in an immediate reduction in urine leukocytes and bacteriuria.