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Abstract：
Dental unit water systems are prone to biofilm formation. During use of the dental unit, clumps of biofilm slough off and can subsequently be aerosolized and inhaled by both patient and staff, potentially causing infections. The aim of this study was to determine the microbial load and microbiome of dental unit water, in the Netherlands, and the factors influencing these parameters. In total, 226 dental units were sampled and heterotrophic plate counts (HPC) were determined on the traditional effluent sample. Of all dental units, 61% exceeded the recommended microbiological guidelines of 100 colony forming units per milliliter. In addition, the microbiome, with additional q-PCR analysis for specific species, was determined on an effluent sample taken immediately after an overnight stagnancy period, in which the biofilm is in its relaxed state. These relaxed biofilm samples showed that each dental unit had a unique microbiome. Legionella spp., amoeba and fungi were found in 71%, 43% and 98% of all units, respectively. The presence of amoeba was positively associated with nine bacterial biomarkers and correlated positively with bacterial and fungal DNA and Legionella spp. concentrations, but not with HPC. Only when adhering to disinfection protocols, statistically significant effects on the microbial load and microbiome were seen. The relaxed biofilm sample, in combination with molecular techniques gives better insight in the presence of opportunistic pathogens when compared to the heterotrophic plate counts. Infection control measures should focus on biofilm analysis and control in order to guarantee patient safety.
摘要：
牙科单元水系统易于形成生物膜。在牙科单元的使用过程中，生物膜团块脱落，随后可被患者和工作人员雾化吸入，可能导致感染。本研究的目的是确定牙科单位水的微生物负荷和微生物组，在荷兰,以及影响这些参数的因素。总的来说,对226个牙科单元进行采样，并在传统的流出物样品上确定异养板计数（HPC）。在所有牙科单位中，61%超过了推荐的微生物指南100个菌落形成单位/毫升。此外,微生物组,对特定物种进行额外的q-PCR分析，是在过夜停滞期后立即采集的流出物样品上确定的，其中生物膜处于松弛状态。这些松弛的生物膜样品显示每个牙科单元具有独特的微生物组。军团菌属。,在71%中发现了变形虫和真菌，43%和98%的所有单位，分别。变形虫的存在与9种细菌生物标志物呈正相关，与细菌和真菌DNA以及军团菌呈正相关。浓度,但不是HPC。只有当遵守消毒协议时，对微生物负荷和微生物组的影响具有统计学意义。松弛的生物膜样品，与异养平板计数相比，结合分子技术可以更好地了解机会病原体的存在。感染控制措施应侧重于生物膜分析和控制，以确保患者安全。
