Liedberg H
Department of Urology, Karolinska Hospital and Institute, Stockholm, Sweden.
Scand J Urol Nephrol Suppl. 1989;124:1-43.
Urinary tract infections accounts for over 40% of all nosocomial infections, and almost all these infections are associated with indwelling catheters. The acquisition of urinary tract infections following urinary bladder catheterizations are associated with nearly a threefold increase in mortality among hospitalized patients. The economic impact of nosocomial urinary infections is difficult to assess. An estimate of the cost of these infections have shown that patients with hospital-acquired urinary tract infections secondary to indwelling catheters, spent an average of 2.4 additional days in the hospital. Bearing this in mind, even a marginal decrease in urinary tract infections may be cost-effective. In two randomized prospective clinical studies we have shown that coating urinary catheters with silver significantly reduces the infection rate during short-term catheterization (less than 7 days). We also showed that silver coating of urinary catheters prevented adherence and growth of Pseudomonas aeruginosa on the catheter material. Another risk from using indwelling catheters is an inflammatory reaction of the urethral mucosa leading to stricture formation. Several aetiological factors whereby indwelling catheters may cause a urethral stricture have been discussed. During the last years much attention has been paid to the catheter material as such, especially latex, and its role in stricture formation. Urinary catheters are made from a variety of materials combined with different chemicals. It seems as if these chemical substances can dissolve from the catheter material, causing inflammatory reactions. Using a cell culture technique with a mouse fibroblast cell line (BALBc/3T3), and an animal model with implantation of catheter material into the urethra, we assessed both in vitro cytotoxicity (IC50) and inflammatory reactions in vivo from different catheter materials. The studies confirmed that especially latex materials do not have both cytotoxic effects and cause considerable inflammation within the urethral mucosa. By coating the catheters with silver, the cytotoxicity could be significantly reduced as compared with pure latex and hydrogel coated latex catheters. Several studies have demonstrated a cytotoxic effect from catheter materials, indicating that this may be of importance in urethral inflammation. However, the exact mechanisms behind this phenomenon is not known. In an attempt to explain the inflammatory reaction within the urethra secondary to an indwelling catheter, we investigated the influence of the nervous system on experimentally induced urethral inflammation. Our findings indicate that an important part in catheter induced inflammation is played by neurogenic reactions.
尿路感染占所有医院感染的40%以上,并且几乎所有这些感染都与留置导尿管有关。膀胱插管后发生的尿路感染会使住院患者的死亡率增加近两倍。医院获得性尿路感染的经济影响难以评估。对这些感染成本的估计表明,因留置导尿管继发医院获得性尿路感染的患者平均要在医院多住2.4天。考虑到这一点,即使尿路感染率有轻微下降也可能具有成本效益。在两项随机前瞻性临床研究中,我们表明用银涂层导尿管可显著降低短期插管(少于7天)期间的感染率。我们还表明,导尿管的银涂层可防止铜绿假单胞菌在导管材料上黏附和生长。使用留置导尿管的另一个风险是尿道黏膜的炎症反应导致狭窄形成。已经讨论了留置导尿管可能导致尿道狭窄的几种病因。在过去几年中,人们对导管材料本身,尤其是乳胶,及其在狭窄形成中的作用给予了很多关注。导尿管由多种材料与不同化学物质组合制成。似乎这些化学物质会从导管材料中溶解出来,引起炎症反应。我们使用小鼠成纤维细胞系(BALBc/3T3)的细胞培养技术以及将导管材料植入尿道的动物模型,评估了不同导管材料的体外细胞毒性(IC50)和体内炎症反应。研究证实,尤其是乳胶材料既具有细胞毒性作用,又会在尿道黏膜内引起相当程度的炎症。与纯乳胶和水凝胶涂层乳胶导尿管相比,通过用银涂层导尿管,细胞毒性可显著降低。几项研究已经证明导管材料具有细胞毒性作用,表明这可能在尿道炎症中起重要作用。然而,这一现象背后的确切机制尚不清楚。为了解释留置导尿管继发的尿道内炎症反应,我们研究了神经系统对实验性诱导的尿道炎症的影响。我们的研究结果表明,神经源性反应在导管诱导的炎症中起重要作用。