摘要

       载银不锈钢（Ag-SS）用于生活热水系统（DHWS）以控制生物膜污染。以 SS 作为对照，研究了 Ag-SS 的抗菌特性，以及管壁生物膜的细菌群落、潜在病原体和抗生素抗性基因 (ARG)。 Ag-SS 通过接触抑菌对异养细菌 (70.60 ± 13.22 %) 和大肠杆菌 (73.56 ± 10.62 %) 保持高抗菌效率。优势门在 Ag-SS 中的相对丰度低于 SS。细菌进一步分为丰富（≥ 1 %）、中等丰富（0.1∼1 %）和稀有（≤ 0.1 %）分类群，以研究它们对银的反应。有 15.33% 的共享操作分类单元 (OTU) 属于丰富的分类群，而每个样本的大多数独特的 OTU (> 80 %) 被确定为稀有分类群。作为主要丰富的属，Mesorhizobium 和 Bradyrhizobium 分别对银表现出抗性和敏感性。大多数占优势的中等丰富和稀有属对银具有抗性。此外，在检测到的19种潜在病原体中，军团菌、副衣原体和气单胞菌对银敏感，假单胞菌和不动杆菌对银敏感。此外，总共检测到 48 个 ARG，它们在两个样本中表现出相似的分布。与 SS 相比，Ag-SS 中 ARGs 的总丰度增加了 0.08 倍，外排泵是主要的抵抗机制。本研究突出了丰富、中等丰富和稀有类群对银的不同反应，以及 ARGs 的发生，证实了 Ag-SS 是一种有效的消毒策略，可保护 DHWS 的生物安全。

       Silver-loaded stainless steel (Ag-SS) was applied in domestic hot water system (DHWS) to control the biofilm contamination. The antibacterial properties of Ag-SS, as well as the bacterial communities, potential pathogens and antibiotic resistance genes (ARGs) of pipe wall biofilm were investigated, with SS as control. Ag-SS maintained a high antibacterial efficiency on heterotrophic bacteria (70.60 ± 13.22 %) and Escherichia coli (73.56 ± 10.62 %) by contact bacteriostasis. Dominant phyla exhibited a lower relative abundance in Ag-SS than SS. The bacteria were further classified into abundant (≥ 1 %), moderately abundant (0.1∼1 %) and rare (≤ 0.1 %) taxa to investigate their responses to silver. There were 15.33 % of shared operational taxonomic units (OTUs) belonged to abundant taxa, while most unique OTUs (> 80 %) of each sample were identified as rare taxa. As the primary abundant genera, Mesorhizobium and Bradyrhizobium exhibited resistant and sensitive to silver, respectively. Most dominant moderately abundant and rare genera were resistant to silver. Moreover, among 19 detected potential pathogens, Legionella, Parachlamydia and Aeromonas were sensitive to silver, while Pseudomonas and Acinetobacter were resistant to silver. Furthermore, a total of 48 ARGs were detected and they exhibited similar distributions in both samples. The total abundance of ARGs in Ag-SS increased by 0.08 fold compared with that in SS, with efflux pumps as the main resistance mechanisms. This study highlights the different responses of abundant, moderately abundant and rare taxa to silver, and the occurrences of ARGs, confirming that Ag-SS was an effective disinfection strategy for biosafety protection of DHWS.

https://www.sciencedirect.com/science/article/abs/pii/S2214714421000222