Rationale & Objective

Contaminated water and other fluids are increasingly recognized to be associated with health care–associated infections. We investigated an outbreak of Gram-negative bloodstream infections at 3 outpatient hemodialysis facilities.

Study Design

Matched case-control investigations.

Setting & Participants

Patients who received hemodialysis at Facility A, B, or C from July 2015 to November 2016.

Exposures

Infection control practices, sources of water, dialyzer reuse, injection medication handling, dialysis circuit priming, water and dialysate test findings, environmental reservoirs such as wall boxes, vascular access care practices, pulsed-field gel electrophoresis, and whole-genome sequencing of bacterial isolates.

Outcomes

Cases were defined by a positive blood culture for any Gram-negative bacteria drawn July 1, 2015 to November 30, 2016 from a patient who had received hemodialysis at Facility A, B, or C.

Analytical Approach

Exposures in cases and controls were compared using matched univariate conditional logistic regression.

Results

58 cases of Gram-negative bloodstream infection occurred; 48 (83%) required hospitalization. The predominant organisms were Serratia marcescens (n = 21) and Pseudomonas aeruginosa (n = 12). Compared with controls, cases had higher odds of using a central venous catheter for dialysis (matched odds ratio, 54.32; lower bound of the 95% CI, 12.19). Facility staff reported pooling and regurgitation of waste fluid at recessed wall boxes that house connections for dialysate components and the effluent drain within dialysis treatment stations. Environmental samples yielded S marcescens and P aeruginosa from wall boxes. S marcescens isolated from wall boxes and case-patients from the same facilities were closely related by pulsed-field gel electrophoresis and whole-genome sequencing. We identified opportunities for health care workers’ hands to contaminate central venous catheters with contaminated fluid from the wall boxes.

Limitations

Limited patient isolates for testing, on-site investigation occurred after peak of infections.

Conclusions

This large outbreak was linked to wall boxes, a previously undescribed source of contaminated fluid and biofilms in the immediate patient care environment.

中文翻译：

---

血液透析患者革兰氏阴性血流感染的多中心暴发

理由与目标

人们日益认识到，污水和其他液体与卫生保健相关的感染有关。我们调查了3家门诊血液透析设施爆发的革兰氏阴性血流感染。

学习规划

匹配的病例对照调查。

设置与参与者

从2015年7月至2016年11月在设施A，B或C接受血液透析的患者。

曝光量

感染控制措施，水源，透析器重复使用，注射药物处理，透析回路灌注，水和透析液测试结果，壁箱等环境储液器，血管通路护理措施，脉冲场凝胶电泳以及细菌的全基因组测序隔离株。

结果

根据2015年7月1日至2016年11月30日从A，B或C设施接受血液透析的患者抽取的任何革兰氏阴性细菌的阳性血液培养确定病例。

分析方法

使用匹配的单变量条件对数回归比较病例和对照的暴露。

结果

发生革兰阴性血流感染58例。48名患者（83％）需要住院。主要的生物是粘质沙雷氏菌（n = 21）和铜绿假单胞菌（n = 12）。与对照组相比，病例使用中心静脉导管进行透析的几率更高（匹配几率比为54.32； 95％CI的下限为12.19）。设施工作人员报告说，在透析箱内的透析箱内装有用于透析液成分和废水排放的连接处的壁橱中，废水积聚和回流。环境样品从壁盒中产生了marcescens和铜绿假单胞菌。苦苣菜通过脉冲场凝胶电泳和全基因组测序，从墙盒中分离出的病例和来自同一机构的病例患者密切相关。我们发现了医护人员的双手被壁箱中的污染流体污染中心静脉导管的机会。

局限性

有限的患者分离株进行测试，感染高峰后进行现场调查。

结论

这次大规模的爆发与壁箱有关，壁箱是之前未描述的在直接患者护理环境中污染的液体和生物膜的来源。