Wenzler-Röttele S, Dettenkofer M, Schmidt-Eisenlohr E, Gregersen A, Schulte-Mönting J, Tvede M
Institute of Environmental Medicine and Hospital Epidemiology, Freiburg University Hospital, Hugstetter Str. 55, 79106, Freiburg, Germany.
Infection. 2006 Aug;34(4):214-8. doi: 10.1007/s15010-006-5626-2.
Catheter-associated urinary tract infection is the most common nosocomial infection in clinical settings. For bacteria ascending to the bladder the most common route is the extraluminal, but the intraluminal route also plays a role. For this reason, we compared two urinary closed system bags (CSB), one with a double and the other with a single non-return valve (NRV), in a laboratory setting in order to establish their ability to prevent or delay the ascent of bacteria from the drainage bag to the bladder.
The tests were performed in two microbiological laboratories (Copenhagen (C), Denmark and Freiburg (F), Germany). These were blinded to each other. A urinary tract model using artificial urine was set up. Two sets of ten drainage bags each with a double NRV (CSB A), and two sets of ten drainage bags each with a single NRV (CSB B) were inoculated with Escherichia coli (F: ATCC 25922; C: clinical strain). Daily samples were taken from two drainage ports on each system - one above the NRV (Port I), the other above the top of the artificial bladder (Port II). Time till E. coli was detected at the drainage ports (time to positivity) was measured. Colonization of the 'bladder' was defined as time to positivity at Port II.
No significant differences in time to positivity at Port I (median 9.0, range: 6-12 for CSB B vs median 9.5 days, range: 6-13 for CSB A) were observed between the two systems. However, substantial differences were seen between the two systems in time to positivity at Port II: Port II on the bladder model using CSB B became positive after a median of 14.0 days (range: 10-22), whereas Port II of the model using CSB A only became positive after 21.5 days (range: 13-24). This amounts to a highly significant difference of 7.5 days (p = 0.0001) in the mean.
Under laboratory conditions, colonization of the 'bladder' was significantly delayed when the CSB with a double NRV was used in comparison to the results obtained from the single NRV-system. Clinical trials should be conducted to investigate whether the urinary CSB with the double NRV has the ability to prevent (or to delay the onset of) catheter-associated urinary tract infection.
导尿管相关尿路感染是临床环境中最常见的医院感染。对于上行至膀胱的细菌，最常见的途径是腔外途径，但腔内途径也起作用。因此，我们在实验室环境中比较了两种尿液封闭系统袋（CSB），一种带有双止回阀，另一种带有单止回阀（NRV），以确定它们预防或延迟细菌从引流袋上行至膀胱的能力。
测试在两个微生物实验室（丹麦哥本哈根（C）和德国弗莱堡（F））进行。这两个实验室相互不知情。建立了使用人工尿液的尿路模型。两组各十个带有双NRV的引流袋（CSB A）和两组各十个带有单NRV的引流袋（CSB B）接种大肠杆菌（F：ATCC 25922；C：临床菌株）。每天从每个系统的两个引流口取样——一个在NRV上方（端口I），另一个在人工膀胱顶部上方（端口II）。测量在引流口检测到大肠杆菌的时间（阳性时间）。“膀胱”的定植定义为端口II的阳性时间。
在两个系统之间，未观察到端口I的阳性时间有显著差异（CSB B的中位数为9.0天，范围：6 - 12天；CSB A的中位数为9.5天，范围：6 - 13天）。然而，在端口II的阳性时间方面，两个系统之间存在显著差异：使用CSB B的膀胱模型上的端口II在中位数为14.0天（范围：10 - 22天）后变为阳性，而使用CSB A的模型的端口II在21.5天（范围：13 - 24天）后才变为阳性。这意味着平均差异高达7.5天（p = 0.0001），具有高度显著性。
在实验室条件下，与单NRV系统相比，使用带有双NRV的CSB时，“膀胱”的定植显著延迟。应进行临床试验以研究带有双NRV的尿液CSB是否有能力预防（或延迟）导尿管相关尿路感染的发生。
