PDF(Pubmed)
Abstract：
Toilets contaminated with infectious organisms are a recognized contact disease transmission hazard. Previous studies indicate that toilet bowl water can remain contaminated for several flushes after the contamination occurs. This study characterized contamination persistence over an extended series of flushes using both indicator particles and viable bacteria. For this study, toilets were seeded with microbe-size microbial surrogates and with Pseudomonas fluorescens or Clostridium difficile bacteria and flushed up to 24 times. Bowl water samples collected after seeding and after each flush indicated the clearance per flush and residual bowl water contaminant concentration. Toilets exhibited 3 + log10 contaminant reductions with the first flush, only 1-2 logs with the second flush, and less than 1 log thereafter. Contamination still was present 24 flushes post contamination. Clearance was modeled accurately by a two-stage exponential decay process. This study shows that toilet bowl water will remain contaminated many flushes after initial contamination, posing a risk of recurring environmental contamination and associated infection incidence.
摘要：
被传染性生物污染的厕所是公认的接触性疾病传播危害。先前的研究表明，在污染发生后，厕所的水可能会在几次冲洗中保持污染。这项研究使用指示剂颗粒和活细菌表征了一系列冲洗过程中的污染持久性。对于这项研究，用微生物大小的微生物替代物和荧光假单胞菌或艰难梭菌接种厕所，冲洗多达24次。播种后和每次冲洗后收集的碗水样品表明每次冲洗的清除率和残留的碗水污染物浓度。厕所在第一次冲洗时表现出3+log10污染物减少，只有1-2个日志与第二次同花顺，此后少于1个日志。污染仍存在24次污染后冲洗。间隙通过两阶段指数衰减过程精确建模。这项研究表明，在初次污染后，许多冲水都会被污染，存在反复发生的环境污染和相关感染发生率的风险。
