Division of Infection and Immunity, University College London, London, UK.
University College London Hospitals NHS Foundation Trust, London, UK.
J Hosp Infect. 2022 Dec;130:1-6. doi: 10.1016/j.jhin.2022.08.007. Epub 2022 Aug 30.
Pseudomonas aeruginosa in hospital water is a risk for invasive infection. Point-of-use (POU) filters are used to reduce patient exposure to the organism, and hollow-fibre filters are becoming more popular. However, retrograde colonization of the filter mechanism may contaminate the effluent.
To assess the efficacy of POU filter head (polysulfone; hollow-fibre matrix) shower filters in preventing the exposure of high-risk patient groups to P. aeruginosa.
Pre-flush (opening the outlet and collecting the first 100 mL of water) samples were analysed to measure P. aeruginosa contamination from 25 shower outlets (∼21% of all showers on the six wards), with and without a hollow-fibre filter. P. aeruginosa was measured in a subset of outlets harbouring P. aeruginosa (sampling period 19 August 2019 to 10 January 2020).
Water from all 25 showers was heavily colonized [>300 colony-forming units (cfu)/mL] with P. aeruginosa at the showerhead. P. aeruginosa was found in 32% (8/25) of post-filter shower water effluent samples with a geometric mean of 4x10 cfu/mL (N=4) (6.8x10-2x10). Filters were sampled at 15-150 days of use (median 15 days), with 26% (6/23) of filter units becoming colonized before the expiry date.
POU filter showerhead units may not be effective in preventing exposure of vulnerable patients to P. aeruginosa in hospital water due to retrograde contamination (external contamination of the showerhead passed back to the filter cartridge itself) or failure of the hollow-fibre filter matrix. Reliance should not be placed on the use of hollow-fibre filters to protect patients from exposure to P. aeruginosa without repeated microbiological monitoring.
医院水中的铜绿假单胞菌是侵袭性感染的风险因素。即取即用（POU）过滤器用于减少患者暴露于该生物体的风险，并且中空纤维过滤器越来越受欢迎。然而，过滤器机制的逆行定植可能会污染流出物。
评估 POU 过滤头（聚砜；中空纤维基质）淋浴过滤器在防止高风险患者群体暴露于铜绿假单胞菌中的功效。
分析了 25 个淋浴出口（占六个病房所有淋浴的约 21%）的预冲洗（打开出水口并收集最初的 100 毫升水）样本，以测量有无中空纤维过滤器时的铜绿假单胞菌污染情况。在含有铜绿假单胞菌的一部分出口（采样期为 2019 年 8 月 19 日至 2020 年 1 月 10 日）中测量了铜绿假单胞菌。
所有 25 个淋浴器的水都严重定植了铜绿假单胞菌[>300 个菌落形成单位（cfu）/mL]，在淋浴喷头处。在过滤后的淋浴水出口样本中，有 32%（8/25）的样本中发现了铜绿假单胞菌，几何平均值为 4x10 cfu/mL（N=4）（6.8x10-2x10）。过滤器在使用 15-150 天后进行采样（中位数为 15 天），在截止日期之前有 26%（6/23）的过滤器单元被定植。
由于逆行污染（喷头外部污染被传递回过滤器本身）或中空纤维过滤器基质的失效，POU 过滤淋浴头装置可能无法有效防止脆弱患者暴露于医院水中的铜绿假单胞菌。如果不进行重复的微生物监测，不应依赖中空纤维过滤器来保护患者免受铜绿假单胞菌暴露。
