Shower systems provide unique environments that are conducive to biofilm formation and the proliferation of pathogens. The water heating temperature is a delicate decision that can impact microbial growth, balancing safety and energy consumption. This study investigated the impact of different heating temperatures (39 °C, 45 °C, 51 °C and 58 °C) on the shower hose biofilm (exposed to a final water temperature of 39 °C) using controlled full-scale shower setups. Whole metagenome sequencing and metaproteomics were employed to unveil the microbial composition and protein expression profiles. Overall, the genes and enzymes associated with disinfectant resistance and biofilm formation appeared largely unaffected. However, metagenomic analysis revealed a sharp decline in the number of total (86,371 to 34,550) and unique genes (32,279 to 137) with the increase in hot water temperature, indicating a significant reduction of overall microbial complexity. None of the unique proteins were detected in the proteomics experiments, suggesting smaller variation among biofilms on the proteome level compared to genomic data. Furthermore, out of 43 pathogens detected by metagenomics, only 5 could actually be detected by metaproteomics. Most interestingly, our study indicates that 45 °C heating temperature may represent an optimal balance. It minimizes active biomass (ATP) and reduces the presence of pathogens while saving heating energy. Our study offered new insights into the impact of heating temperature on shower hose biofilm formation and proposed optimal parameters that ensure biosafety while conserving energy.

中文翻译：

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通过多组学揭示加热温度对淋浴软管中生物膜形成的影响


淋浴系统提供独特的环境，有利于生物膜的形成和病原体的增殖。水加热温度是一个微妙的决定，可能会影响微生物的生长，平衡安全和能源消耗。本研究使用受控全尺寸淋浴装置调查了不同加热温度（39 °C、45 °C、51 °C 和 58 °C）对淋浴软管生物膜（暴露于最终水温 39 °C）的影响。采用全宏基因组测序和宏蛋白质组学来揭示微生物组成和蛋白质表达谱。总体而言，与消毒剂耐药性和生物膜形成相关的基因和酶似乎基本不受影响。然而，宏基因组分析显示，随着热水温度的升高，总基因数量（86,371 至 34,550 个）和独特基因（32,279 至 137 个）急剧下降，表明整体微生物复杂性显著降低。在蛋白质组学实验中未检测到任何独特的蛋白质，这表明与基因组数据相比，蛋白质组水平上生物膜之间的差异较小。此外，在宏基因组学检测到的 43 种病原体中，实际上只有 5 种可以通过宏蛋白质组学检测到。最有趣的是，我们的研究表明，45 °C 的加热温度可能代表了最佳平衡。它最大限度地减少了活性生物质 （ATP） 并减少病原体的存在，同时节省了热能。我们的研究为加热温度对淋浴软管生物膜形成的影响提供了新的见解，并提出了在节约能源的同时确保生物安全的最佳参数。