Abstract：
OBJECTIVE: About 50% of individuals with long-term indwelling catheters are affected by catheter encrustations and bladder stone formation. Therefore, prophylaxis of catheter encrustations is important. Currently, however, neither an established prophylaxis nor a standardized in-vitro model to test different measures exist. We have therefore developed and qualitatively evaluated an in-vitro model of catheter encrustation.
METHODS: Size 14 French suprapubic catheters were incubated under sterile conditions at 37 degrees Celsius in five different media: (1) sterile artificial urine (n = 16), (2) artificial urine with E. coli (n = 8), (3) with Pseudomonas aeruginosa (n = 8), (4) with Proteus mirabilis (n = 8), and (5) with a mix of these three strains (n = 8). Catheter balloons were inflated either a glycerine or a bactericidal solution. After 6 weeks, the catheters were removed from the solution, dried, and weighed, and a photometric determination of the retrieved encrustations was performed.
RESULTS: Most frequently and pronounced encrustations were detected in the Pseudomonas group. The median weight of these encrustations (50% struvite and brushite) was 84.4 mg (47.7 mg / 127.3 mg). Even on catheters stored in sterile urine, encrustations (69.2% struvite) were found. Bacterial growth was not affected by the medium used for catheter blockage.
CONCLUSIONS: Although in-vitro models appear to be limited because they lack \"the human factor\", they are valuable for systematically assessing physico-chemical factors affecting encrustations. Therefore, our model, being reliable and cost-effective, may foster further research despite its limitations.
METHODS: Size 14 French suprapubic catheters were incubated under sterile conditions at 37 degrees Celsius in five different media: (1) sterile artificial urine (n = 16), (2) artificial urine with E. coli (n = 8), (3) with Pseudomonas aeruginosa (n = 8), (4) with Proteus mirabilis (n = 8), and (5) with a mix of these three strains (n = 8). Catheter balloons were inflated either a glycerine or a bactericidal solution. After 6 weeks, the catheters were removed from the solution, dried, and weighed, and a photometric determination of the retrieved encrustations was performed.
RESULTS: Most frequently and pronounced encrustations were detected in the Pseudomonas group. The median weight of these encrustations (50% struvite and brushite) was 84.4 mg (47.7 mg / 127.3 mg). Even on catheters stored in sterile urine, encrustations (69.2% struvite) were found. Bacterial growth was not affected by the medium used for catheter blockage.
CONCLUSIONS: Although in-vitro models appear to be limited because they lack \"the human factor\", they are valuable for systematically assessing physico-chemical factors affecting encrustations. Therefore, our model, being reliable and cost-effective, may foster further research despite its limitations.
摘要：
目的：约50%长期留置导尿管的个体受到导管结壳和膀胱结石形成的影响。因此,预防导管结壳很重要。目前,然而,既不存在既定的预防方法,也不存在测试不同措施的标准化体外模型.因此，我们开发并定性评估了导管结壳的体外模型。
方法：尺寸14号法国耻骨上导管在37摄氏度的无菌条件下在五种不同的培养基中孵育：（1）无菌人工尿液（n=16），（2）大肠杆菌人工尿液（n=8），（3）铜绿假单胞菌（n=8），（4）具有奇异变形杆菌（n=8），和(5)这三种菌株的混合(n=8)。导管球囊充入甘油或杀菌溶液。6周后,从溶液中取出导管,干,称重，并对回收的结壳进行了光度测定。
结果：在假单胞菌群中检测到最常见和最明显的结壳。这些结壳(50%鸟粪石和透钙磷石)的中值重量为84.4mg(47.7mg/127.3mg)。即使是储存在无菌尿液中的导管，发现结壳(69.2%鸟粪石)。细菌生长不受用于导管阻塞的培养基的影响。
结论：尽管体外模型似乎受到限制，因为它们缺乏“人为因素”，它们对于系统地评估影响结壳的物理化学因素很有价值。因此,我们的模型,可靠且具有成本效益，尽管有其局限性，但可能会促进进一步的研究。
方法：尺寸14号法国耻骨上导管在37摄氏度的无菌条件下在五种不同的培养基中孵育：（1）无菌人工尿液（n=16），（2）大肠杆菌人工尿液（n=8），（3）铜绿假单胞菌（n=8），（4）具有奇异变形杆菌（n=8），和(5)这三种菌株的混合(n=8)。导管球囊充入甘油或杀菌溶液。6周后,从溶液中取出导管,干,称重，并对回收的结壳进行了光度测定。
结果：在假单胞菌群中检测到最常见和最明显的结壳。这些结壳(50%鸟粪石和透钙磷石)的中值重量为84.4mg(47.7mg/127.3mg)。即使是储存在无菌尿液中的导管，发现结壳(69.2%鸟粪石)。细菌生长不受用于导管阻塞的培养基的影响。
结论：尽管体外模型似乎受到限制，因为它们缺乏“人为因素”，它们对于系统地评估影响结壳的物理化学因素很有价值。因此,我们的模型,可靠且具有成本效益，尽管有其局限性，但可能会促进进一步的研究。
