背景:越来越多的证据表明,医院废水系统在多药耐药生物的传播中起作用,例如产生碳青霉烯酶的肠杆菌(CPE)。根特大学医院老年病房发生了几次连续的CPE暴发,导致了暴发调查。专注于OXA-48生产弗氏柠檬酸杆菌,最普遍的物种,我们旨在使用全基因组测序(WGS)追踪克隆相关性。通过探索传播途径,我们希望增进了解并(重新)引入有针对性的预防措施。
方法:环境筛选(厕所水,水槽和淋浴排水沟)在2017年至2021年之间进行。回顾性选择了53个弗氏柠檬酸杆菌筛选分离株(30名患者和23个环境样本)。提取来自冷冻细菌分离物的DNA并准备用于shot弹枪WGS。使用3,004个基因座,通过内部开发的方案进行核心基因组多位点序列分型。
结果:环境筛查样本的CPE阳性率为19.0%(73/385)。在淋浴排水管样品(38.2%)和厕所水样品(25.0%)中发现了最高的百分比。水槽排水样品显示出最低的CPE阳性(3.3%)。WGS数据揭示了三个患者样品来源的弗氏梭菌簇的长期共存。最大的集群(ST22)连接了2018年至2021年间收集的12名患者和8个环境分离株,分布在整个病房。在重叠的时间段内,另一个集群(ST170)将8名患者和4名厕所水隔离物连接到同一房间。第三个C.freundii集群(ST421)连接了两个在同一房间住院但为期一年半的患者。2022年的额外采样显示,克隆分离株与连接房间的废水收集管道中的两个最大簇(ST22,ST170)相关。
结论:我们的研究结果表明,尽管进行了监测,但在医院卫生设施中产生碳青霉烯酶的克隆的长期循环和传播。日常清洁和间歇消毒方案。我们建议废水排水系统在房间内和房间之间的传播中以及在通过生物气溶胶羽流间接传播中的卫生设施中发挥作用。为了解决这个问题,多学科的方法是必要的,包括仔细的设计和维护的管道系统。
Accumulating evidence shows a role of the hospital wastewater system in the spread of multidrug-resistant organisms, such as carbapenemase producing Enterobacterales (CPE). Several sequential outbreaks of CPE on the geriatric ward of the Ghent University hospital have led to an outbreak investigation. Focusing on OXA-48 producing Citrobacter freundii, the most prevalent species, we aimed to track clonal relatedness using whole genome sequencing (WGS). By exploring transmission routes we wanted to improve understanding and (re)introduce targeted preventive measures.
Environmental screening (toilet water, sink and shower drains) was performed between 2017 and 2021. A retrospective selection was made of 53 Citrobacter freundii screening isolates (30 patients and 23 environmental samples). DNA from frozen bacterial isolates was extracted and prepped for shotgun WGS. Core genome multilocus sequence typing was performed with an in-house developed scheme using 3,004 loci.
The CPE positivity rate of environmental screening samples was 19.0% (73/385). Highest percentages were found in the shower drain samples (38.2%) and the toilet water samples (25.0%). Sink drain samples showed least CPE positivity (3.3%). The WGS data revealed long-term co-existence of three patient sample derived C. freundii clusters. The biggest cluster (ST22) connects 12 patients and 8 environmental isolates taken between 2018 and 2021 spread across the ward. In an overlapping period, another cluster (ST170) links eight patients and four toilet water isolates connected to the same room. The third C. freundii cluster (ST421) connects two patients hospitalised in the same room but over a period of one and a half year. Additional sampling in 2022 revealed clonal isolates linked to the two largest clusters (ST22, ST170) in the wastewater collection pipes connecting the rooms.
Our findings suggest long-term circulation and transmission of carbapenemase producing C. freundii clones in hospital sanitary installations despite surveillance, daily cleaning and intermittent disinfection protocols. We propose a role for the wastewater drainage system in the spread within and between rooms and for the sanitary installations in the indirect transmission via bioaerosol plumes. To tackle this problem, a multidisciplinary approach is necessary including careful design and maintenance of the plumbing system.