Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zürich, Switzerland.
Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zürich, Switzerland.
Water Res. 2018 Mar 15;131:274-286. doi: 10.1016/j.watres.2017.12.027. Epub 2017 Dec 14.
Shower hoses offer an excellent bacterial growth environment in close proximity to a critical end-user exposure route within building drinking water plumbing. However, the health risks associated with and processes underlying the development of biofilms in shower hoses are poorly studied. In a global survey, biofilms from 78 shower hoses from 11 countries were characterized in terms of cell concentration (4.1 × 10-5.8 × 10 cells/cm), metal accumulation (including iron, lead, and copper), and microbiome composition (including presence of potential opportunistic pathogens). In countries using disinfectant, biofilms had on average lower cell concentrations and diversity. Metal accumulation (up to 5 μg-Fe/cm, 75 ng-Pb/cm, and 460 ng-Cu/cm) seemed to be partially responsible for discoloration in biofilms, and likely originated from other pipes upstream in the building. While some genera that may contain potential opportunistic pathogens (Legionella, detected in 21/78 shower hoses) were positively correlated with biofilm cell concentration, others (Mycobacterium, Pseudomonas) had surprisingly non-existent or negative correlations with biofilm cell concentrations. In a controlled study, 15 identical shower hoses were installed for the same time period in the same country, and both stagnant and flowing water samples were collected. Ecological theory of dispersal and selection helped to explain microbiome composition and diversity of different sample types. Shower hose age was related to metal accumulation but not biofilm cell concentration, while frequency of use appeared to influence biofilm cell concentration. This study shows that shower hose biofilms are clearly a critical element of building drinking water plumbing, and a potential target for building drinking water plumbing monitoring.
淋雨花洒在建筑饮用水管道中非常接近关键的终端用户暴露途径，为细菌提供了极佳的生长环境。然而，淋雨花洒中生物膜的发展所涉及的健康风险及其相关过程还研究甚少。在一项全球调查中，对来自 11 个国家的 78 根淋雨花洒中的生物膜进行了特征描述，包括细胞浓度（4.1×105-5.8×105 个细胞/cm）、金属积累（包括铁、铅和铜）以及微生物组组成（包括潜在机会性病原体的存在）。在使用消毒剂的国家中，生物膜的细胞浓度和多样性平均较低。金属积累（高达 5μg-Fe/cm、75ng-Pb/cm 和 460ng-Cu/cm）似乎部分导致了生物膜的变色，并且可能源自建筑物上游的其他管道。虽然一些可能包含潜在机会性病原体的属（军团菌，在 21/78 根淋雨花洒中检测到）与生物膜细胞浓度呈正相关，但其他属（分枝杆菌、假单胞菌）与生物膜细胞浓度的相关性却出乎意料地不存在或呈负相关。在一项对照研究中，在同一国家同一时期安装了 15 根相同的淋雨花洒，并采集了静止和流动水样。扩散和选择的生态理论有助于解释不同样本类型的微生物组组成和多样性。淋雨花洒的使用年限与金属积累有关，但与生物膜细胞浓度无关，而使用频率似乎影响生物膜细胞浓度。本研究表明，淋雨花洒生物膜显然是建筑物饮用水管道的一个关键组成部分，也是建筑物饮用水管道监测的一个潜在目标。
