Watterson James D, Cadieux Peter A, Stickler David, Reid Gregor, Denstedt John D
Division of Urology, University of Western Ontario, London, Ontario, Canada.
J Endourol. 2003 Sep;17(7):523-7. doi: 10.1089/089277903769013711.
Encrustation on indwelling ureteral stents is commonly related to the presence of urease-producing bacteria that elevate the pH of the urine through the hydrolysis of urea, resulting in the precipitation of calcium and magnesium salts. Using a model previously shown to measure accurately the ability of Proteus mirabilis to swarm over catheter surfaces (Eur J Clin Microbiol Infect Dis 1999;18:206), we investigated the ability of this organism to swarm over three ureteral stents with potential encrustation-resistance properties.
Three commercially available ureteral stents were selected for evaluation: a low surface-energy stent, a hydrogel-coated stent, and a silicone stent. Ten-microliter aliquots of a 4-hour culture of P. mirabilis 296 in Trypticase soya (TSA) broth was inoculated 5 mm from a 1-cm channel cut out from TSA plates. Ten-millimeter stent sections were placed as bridges across the central channel adjacent to the inocula. Time to pathogen crossing was measured.
The mean time (+/- SD) to pathogen migration across the three test materials was 15.9 +/- 6.1, 19.8 +/- 9.5, and 29.7 +/- 14.3 hours for the low surface-energy, hydrogel-coated, and silicone stents, respectively. Statistical analysis revealed significant differences between the crossing times of the low surface-energy (P = 0.001) and hydrogel-coated (P = 0.034) stents compared with silicone but not between the low surface-energy and hydrogel-coated stents (P = 0.387).
Migration of P. mirabilis 296 across silicone stents was significantly reduced compared with low surface-energy and hydrogel-coated stents. These findings suggest that P. mirabilis may have a lower affinity for silicone stents, which may translate into a reduced risk of infection with P. mirabilis and associated stent encrustation.
留置输尿管支架上的结痂通常与产脲酶细菌的存在有关，这些细菌通过尿素水解使尿液pH值升高，导致钙盐和镁盐沉淀。我们使用先前已证明能准确测量奇异变形杆菌在导管表面群集能力的模型（《欧洲临床微生物学与传染病杂志》1999年；18:206），研究了这种微生物在三种具有潜在抗结痂特性的输尿管支架上群集的能力。
选择三种市售输尿管支架进行评估：低表面能支架、水凝胶涂层支架和硅胶支架。从胰蛋白酶大豆（TSA）平板上切出1厘米的通道，在距通道5毫米处接种10微升奇异变形杆菌296在胰蛋白酶大豆肉汤中培养4小时的菌液。将10毫米长的支架段作为桥梁横跨在靠近接种物的中央通道上。测量病原体穿过的时间。
病原体在三种测试材料上迁移的平均时间（±标准差），低表面能支架为15.9±6.1小时，水凝胶涂层支架为19.8±9.5小时，硅胶支架为29.7±14.3小时。统计分析显示，与硅胶支架相比，低表面能支架（P = 0.001）和水凝胶涂层支架（P = 0.034）的穿过时间存在显著差异，但低表面能支架和水凝胶涂层支架之间无显著差异（P = 0.387）。
与低表面能支架和水凝胶涂层支架相比，奇异变形杆菌296在硅胶支架上的迁移明显减少。这些发现表明，奇异变形杆菌对硅胶支架的亲和力可能较低，这可能意味着感染奇异变形杆菌及相关支架结痂的风险降低。
