Assessment of Bacterial Communities Within the Biofilm of Bladder Calculi in the Neurogenic Bladder Rat Model Following Spinal Cord Injury

Purpose: To develop a rat model of bladder calculi in the neurogenic bladder following spinal cord injury (SCI) and assess bacterial communities within the biofilm of bladder calculi using denaturing gradient gel electrophoresis (DGGE). Methods: The silk tied to a small segment of the Teflon IV catheter was implanted through the urethra into the bladder of rats with SCI induced by T9 laminectomy. After 6 months, the rats were sacrificed and their bladder calculi were collected by opening the bladders through the low-midline incision. Genomic DNA was extracted from the biofilm of bladder calculi fol-lowed by DGGE to obtain bacterial DNA. The DNA sequences were compared and analyzed using BLAST (Basic Local Alignment Search Tool) to identify bacteria. Results: After placing silk nidus in the bladder for 6 months, all 6 rats developed bladder calculi. According to DGGE analysis, Pseudomonas aeruginosa was the most dominant strain, while Clostridium sp. and Lactobacillus sp. were relatively dominant strains within the biofilm of bladder calculi in the rats with SCI. Conclusions: DGGE analysis showed various microorganisms in the biofilm of calculi arising from a neurogenic bladder rat model. This research design can be the basis for clinical studies and may be applied to calculi in patients with neurogenic blad-der following SCI.