Shotgun Metagenomics Reveals Taxonomic and Functional Shifts in Hot Water Microbiome Due to Temperature Setting and Stagnation
Shotgun Metagenomics Reveals Taxonomic and Functional Shifts in Hot Water Microbiome Due to Temperature Setting and Stagnation
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DOI：
10.3389/fmicb.2018.02695
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发表时间：
2018-11-13
影响因子：
5.2
通讯作者：
Pruden, Amy
中科院分区：
文献类型：
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作者：
Dai, Dongjuan;Rhoads, William J.;Pruden, Amy
热水前提管道已成为能源，水和公共卫生的关键联系。热水微生物组的组成是特别感兴趣的，因为人类每天暴露于常驻植物群，特别是条件致病菌（OP），其依赖于复杂的微生物生态相互作用来增殖。在这里，我们应用鸟枪宏基因组测序来表征微生物组的分类和功能变化，作为热水器温度设置，远端管道停滞以及水化学相关变化的函数。来自受控的、重复的、中试规模的热水管道装置的样品的横截面代表不同的温度设置（39、42和51摄氏度）、停滞期（8小时与7天）和时间点，进行了分析。温度设置的分类和功能基因组成的总体影响。此外，通过特定的温度设置（例如，军团菌在39摄氏度与异常球菌在51摄氏度），而编码相应细胞功能的基因的相对丰度与基于驱动这些变化的分类群的预期高度一致。远端水龙头的停滞减少了在循环管线中将冷进水加热为热水所引起的分类和功能差异。在相对于再循环热水的远端龙头中，注释为参与代谢和生长的读数减少，而对应于应激反应的注释（例如，毒力疾病和防御，特别是抗生素抗性）增加。通过宏基因组分析容易地鉴定对应于OP的读段，其中L.尤其是肺炎球菌读数与通过定量聚合酶链反应测量的基因拷贝数非常好地相关。L.还鉴定了嗜肺菌读数和已知原生动物宿主的读数。注意到编码金属抗性和氢代谢的基因比例升高，这与腐蚀诱导的金属浓度升高和氢产生一致。这项研究为影响热水微生物组分类和功能组成的现实因素提供了新的见解。在这里，宏基因组学被证明是一种有效的工具，用于筛选潜在的存在，甚至数量的病原体，同时还提供诊断能力，用于评估微生物组对各种操作条件的功能反应。这些发现有助于为未来的监测和有意控制热水微生物提供信息。
Hot water premise plumbing has emerged as a critical nexus of energy, water, and public health. The composition of hot water microbiomes is of special interest given daily human exposure to resident flora, especially opportunistic pathogens (OPs), which rely on complex microbial ecological interactions for their proliferation. Here, we applied shotgun metagenomic sequencing to characterize taxonomic and functional shifts in microbiomes as a function of water heater temperature setting, stagnation in distal pipes, and associated shifts in water chemistry. A cross-section of samples from controlled, replicated, pilot-scale hot water plumbing rigs representing different temperature settings (39, 42, and 51 degrees C), stagnation periods (8 h vs. 7 days), and time-points, were analyzed. Temperature setting exhibited an overarching impact on taxonomic and functional gene composition. Further, distinct taxa were selectively enriched by specific temperature settings (e.g., Legionella at 39 degrees C vs. Deinococcus at 51 degrees C), while relative abundances of genes encoding corresponding cellular functions were highly consistent with expectations based on the taxa driving these shifts. Stagnation in distal taps diminished taxonomic and functional differences induced by heating the cold influent water to hot water in recirculating line. In distal taps relative to recirculating hot water, reads annotated as being involved in metabolism and growth decreased, while annotations corresponding to stress response (e.g., virulence disease and defense, and specifically antibiotic resistance) increased. Reads corresponding to OPs were readily identified by metagenomic analysis, with L. pneumophlla reads in particular correlating remarkably well with gene copy numbers measured by quantitative polymerase chain reaction. Positive correlations between L. pneumophila reads and those of known protozoan hosts were also identified. Elevated proportions of genes encoding metal resistance and hydrogen metabolism were noted, which was consistent with elevated corrosion-induced metal concentrations and hydrogen generation. This study provided new insights into real-world factors influencing taxonomic and functional compositions of hot water microbiomes. Here metagenomics is demonstrated as an effective tool for screening for potential presence, and even quantities, of pathogens, while also providing diagnostic capabilities for assessing functional responses of microbiomes to various operational conditions. These findings can aid in informing future monitoring and intentional control of hot water microbiomes.