Cardiff School of Biosciences, Cardiff University, Cardiff, UK.
J Intern Med. 2014 Aug;276(2):120-9. doi: 10.1111/joim.12220.
This review is largely based on a previous paper published in the journal Spinal Cord. The care of many patients undergoing long-term bladder catheterization is complicated by encrustation and blockage of their Foley catheters. This problem stems from infection by urease-producing bacteria, particularly Proteus mirabilis. These organisms colonize the catheter forming an extensive biofilm; they also generate ammonia from urea, thus elevating the pH of urine. As the pH rises, crystals of calcium and magnesium phosphates precipitate in the urine and in the catheter biofilm. The continued development of this crystalline biofilm blocks the flow of urine through the catheter. Urine then either leaks along the outside of the catheter and the patient becomes incontinent or is retained causing painful distension of the bladder and reflux of urine to the kidneys. The process of crystal deposition can also initiate stone formation. Most patients suffering from recurrent catheter encrustation develop bladder stones. P. mirabilis establishes stable residence in these stones and is extremely difficult to eliminate from the catheterized urinary tract by antibiotic therapy. If blocked catheters are not identified and changed, serious symptomatic episodes of pyelonephritis, septicaemia and endotoxic shock can result. All types of Foley catheters including silver- or nitrofurazone-coated devices are vulnerable to this problem. In this review, the ways in which biofilm formation on Foley catheters is initiated by P. mirabilis will be described. The implications of understanding these mechanisms for the development of an encrustation-resistant catheter will be discussed. Finally, the way forward for the prevention and control of this problem will be considered.
这篇综述主要基于之前发表在《脊髓》杂志上的一篇论文。许多长期进行膀胱导尿的患者的护理因 Foley 导尿管的结垢和堵塞而变得复杂。这个问题源于产脲酶细菌，尤其是奇异变形杆菌的感染。这些生物定植在导管上形成广泛的生物膜；它们还从尿素中产生氨，从而提高尿液的 pH 值。随着 pH 值的升高，钙和镁磷酸盐的晶体在尿液和导管生物膜中沉淀。这种结晶生物膜的持续发展会阻塞尿液通过导管的流动。尿液要么从导管外漏，导致患者失禁，要么被保留，导致膀胱疼痛扩张和尿液反流到肾脏。晶体沉积的过程也会引发结石形成。大多数反复发生导管结垢的患者都会形成膀胱结石。奇异变形杆菌在这些结石中建立了稳定的居住地，通过抗生素治疗极难从导尿管尿路中消除。如果不识别和更换堵塞的导管，可能会导致严重的肾盂肾炎、败血症和内毒素休克症状发作。所有类型的 Foley 导管，包括镀银或呋喃妥因涂层的导管，都容易受到这个问题的影响。在这篇综述中，将描述奇异变形杆菌如何引发 Foley 导管上生物膜的形成。讨论了解这些机制对开发抗结垢导管的意义。最后，将考虑预防和控制这个问题的前进方向。
