Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China.
Water Res. 2019 Nov 15;165:114979. doi: 10.1016/j.watres.2019.114979. Epub 2019 Aug 13.
Microplastics have been found to be ubiquitous in freshwater ecosystems, providing a novel substrate for biofilm formation. Here, we incubated biofilm on microplastics and two natural substrates (rock and leaf) under a controlled environment to investigate the differences of microbial community structure, antibiotic resistance gene (ARG) profiles, and ARG microbial hosts between biofilms on three types of substrates. Results from high-throughput sequencing of 16S rRNA gene revealed that microplastic biofilm had a distinctive community structure. Network analyses suggested that microplastic biofilm possessed the highest node connected community, but with lower average path length, network diameter and modularity compared with biofilm on two natural particles. Metagenomic analyses further revealed microplastic biofilm with broad-spectrum and distinctive resistome. Specifically, according to taxonomic annotation of ARG microbial hosts, two opportunisitic human pathogens (Pseudomonas monteilii, Pseudomonas mendocina) and one plant pathogen (Pseudomonas syringae) were detected only in the microplastic biofilm, but not in biofilms formed on natural substrates. Our findings suggest that microplastic is a novel microbial niche and may serve as a vector for ARGs and pathogens to new environment in river water, generating freshwater environmental risk and exerting adverse impacts on human health.
微塑料已被发现广泛存在于淡水生态系统中，为生物膜的形成提供了一种新的基质。在这里，我们在受控环境下将生物膜在微塑料和两种天然基质（岩石和叶子）上进行孵育，以研究三种基质上生物膜的微生物群落结构、抗生素抗性基因（ARG）谱和 ARG 微生物宿主之间的差异。16S rRNA 基因高通量测序的结果表明，微塑料生物膜具有独特的群落结构。网络分析表明，与两种天然颗粒上的生物膜相比，微塑料生物膜具有最高的节点连接群落，但平均路径长度、网络直径和模块度较低。宏基因组学分析进一步揭示了微塑料生物膜具有广谱和独特的抗药性组。具体来说，根据 ARG 微生物宿主的分类注释，只有在微塑料生物膜中检测到两种机会性病原体（假单胞菌 monteilii、假单胞菌 mendocina）和一种植物病原体（丁香假单胞菌），而在天然基质形成的生物膜中则没有检测到。我们的研究结果表明，微塑料是一种新的微生物栖息地，可能成为 ARGs 和病原体向河水新环境传播的载体，从而产生淡水环境风险，并对人类健康产生不利影响。
