摘要

       水生生态系统中微塑料 (MPs) 的微生物定植是一个众所周知的现象；然而，人们对早期殖民阶段的了解不足。污水处理厂 (WWTP) 出水被认为是 MPs 在水生环境中进入和运输的重要途径，并且是细菌病原体和抗生素抗性基因 (ARGs) 的热点。本研究旨在表征部署在两种不同污水处理厂流出物中的七种不同类型 MP 生物膜形成早期的细菌群落，并测量测试 MP 上两种 ARG（sulI 和 tetM）的相对丰度。 16S rRNA 的 Illumina Miseq 测序显示，与 WWTP 流出物中的自由生活细菌相比，MP 上的细菌多样性显着更高。 β-多样性分析表明，原位环境（采样点）和疏水性在较小程度上在早期细菌定植阶段起作用。可以确定早期定植阶段 MPs 核心微生物组。此外，每种类型聚合物的特定核心微生物组表明每种类型都可能选择细菌的早期附着。尽管测试的污水处理厂出水含有携带 sulI 和 tetM ARG 的抗生素抗性细菌 (ARB)，但 MP 浓缩了携带 sulI 基因但不携带 tetM 的 ARB。这些结果强调了早期附着阶段与不同类型 MP 聚合物上细菌生物膜发展的相关性，以及不同类型聚合物可能促进特定细菌附着的作用，其中一些细菌可能携带 ARG。

       Microbial colonization of microplastics (MPs) in aquatic ecosystems is a well-known phenomenon; however, there is insufficient knowledge of the early colonization phase. Wastewater treatment plant (WWTP) effluents have been proposed as important pathways for MPs entry and transport in aquatic environments and are hotspots of bacterial pathogens and antibiotic resistance genes (ARGs). This study aimed at characterizing bacterial communities in the early stage of biofilm formation on seven different types of MPs deployed in two different WWTPs effluents as well as measuring the relative abundance of two ARGs (sulI and tetM) on the tested MPs. Illumina Miseq sequencing of the 16S rRNA showed significant higher diversity of bacteria on MPs in comparison with free-living bacteria in the WWTP effluents. β-diversity analysis showed that the in situ environment (sampling site) and hydrophobicity, to a lesser extent, had a role in the early bacterial colonization phase. An early colonization phase MPs-core microbiome could be identified. Furthermore, specific core microbiomes for each type of polymer suggested that each type might select early attachment of bacteria. Although the tested WWTP effluent waters contained antibiotic resistant bacteria (ARBs) harboring the sulI and tetM ARGs, MPs concentrated ARBs harboring the sulI gene but not tetM. These results highlight the relevance of the early attachment phase in the development of bacterial biofilms on different types of MP polymers and the role that different types of polymers might have facilitating the attachment of specific bacteria, some of which might carry ARGs.

https://www.sciencedirect.com/science/article/abs/pii/S0048969720373630