导尿管抑菌涂层的研究进展

由导尿管引发的尿路感染(CAUTI)是医院常见的感染，在各种院内感染中的占比高达20%~30%，极大地影响了病人的生命健康。目前，基于导尿管表面生物膜生成及无机盐沉积等问题，研究人员提出了多种方法来预防或改善，以实现导尿管的抗菌和抗阻塞性能，如导尿管表面涂层构建、改进导尿管的结构设计、缩短临床使用时间等。综述了近年来导尿管表面抗菌涂层的研究进展，主要从物理改性和化学改性等方面展开。物理改性方法一般通过将聚乙二醇、聚两性离子、抑菌酶等沉积在导管表面，或在导管表面进行仿生微纳结构修饰等，以达到润滑和降低细菌黏附的效果。化学改性方法主要通过将可直接作用于细菌的药物或者因子(包括分子泵抑制剂、抗生素、一氧化氮、抗菌肽等)附着在导尿管表面，以达到抑菌、延长导管堵塞时间等目的。在此基础上，通过对当前导尿管研究趋势的总结及思考，对未来导尿管的功能、抑菌机制及验证等方面进行展望，以期为导尿管抑菌材料的选择和设计提供一定的指导。

Research Progress of Bacteriostatic Coating for Urethral Catheter

Catheter-related urinary tract infection (CAUTI) is a common infection in hospitals, accounting for up to 20%-30% of all nosocomial infections, which greatly affects the quality and health of patients. Urinary tract infections and blocked catheters are mainly caused by the following processes:Urethral infection induced by urethral mucosa injury and invasion of external pathogens are the main sources for CAUTI; bacterial colonization and the formation of biofilm; expression of bacterial urease and catalyses conversion of urease to ammonia and carbon dioxide; elevation of urinary pH and local supersaturation and precipitation of struvite and apatite salts; formation of crystalline biofilms and obstruction of urine flow and catheter blockage. Based on the formation of biofilm and deposition of inorganic salts on catheter, researchers have proposed many methods to prevent CAUTI to realize the antibacterial and anti-blocking capability, such as catheter surface coating, structure design of the catheter , short time for clinical use, etc. There are different methods, directions and ranges to review and conclude the latest research progress concerning the antibacterial coatings on urethral catheter. For example, it can review the research progress from engineering and medical perspectives in prevention of encrustation and blockage of long-term indwelling catheters; it can also review current understanding of bacterial biofilm formation on urethral catheters, crystalline biofilm formation as well as approaches that may be used to control biofilm formation on these devices. This paper mainly reviewed the research progress of antibacterial coating on ureter surface from physical modification and chemical modification in recent years, especially paying attention to the antibacterial activity and anti-blocking effect. The physical modification methods were mainly aimed at inhibiting bacterial adhesion, and acting on the initial stage of bacterial adhesion, colonization, proliferation and biofilm formation. The physical modification method usually used polyethylene glycol, bacteriostatic enzymes or polyzwitterion hydrogel coating to wrap the surface of catheter, or modify the surface micro-nano structure of the catheter to achieve the effect of lubrication and reduce the inhibition of bacterial adhesion. Chemical modification methods were based on the direct action of drugs or proteins on bacteria, which can affect the whole process of bacterial adhesion, colonization, proliferation and biofilm formation. Chemical modification methods mainly summarized the substances that can directly act on bacteria, including molecular pump inhibitors, antibiotics, nitric oxide and antimicrobial peptides, and attached these drugs or factors on the surface of catheter to achieve bacteriostasis, and prolonged the plugging time of the catheter. On this basis, by summarizing the current research process of antibacterial coating on urethral catheters, the function, antibacterial mechanism and validation of urethral catheters in the future were prospected in order to provide some guidance for the selection and design of urethral bacteriostatic materials in the future. It mainly included:multi-antibacterial mechanism can be used to reduce bacterial resistance and prolong the effective time of indwelling catheter, and the important factors during the process from bacterial infection to catheter blockage can be real-time monitored. It can transform the current continuous passive release of drugs into active intelligent release, in vitro culture can be combined with in vivo experiments to test its effectiveness.