摘要

       海水养殖沉淀物被认为是环境抗生素耐药基因（ARGs）的主要贡献者，这对全球感染的治疗具有挑战性。抗生素和鱼粉都被用于水产养殖，它们都有可能促进ARG的传播，但是它们对沉积物抗性的综合影响及其相对贡献尚不清楚。在这项研究中，微观结构暴露于不同浓度的四环素（含或不含鱼粉（0.1%wt/wt））中14天。采用高通量定量PCR和16srRNA基因扩增子测序技术，分析了海水养殖底泥中鱼粉和四环素对抗生素抗性和细菌群落的贡献。检测到67个ARGs可能与几种主要抗生素的耐药性有关。鱼粉，而不是四环素的剂量，有助于显著增加ARG的丰度和多样性在沉积物中。在主坐标分析和层次聚类的基础上，根据是否添加鱼粉将arg分为两组。鱼粉中氨基糖苷类、大环内酯类林可酰胺类链球菌b（MLSb）和四环素抗性基因含量最高，而流动基因元素（MGE）含量也显著增加（P<0.05）。同时，两组间细菌群落结构有明显差异（Adonis，P<0.05）。采用Mantel检验和偏最小二乘路径模型，我们发现沉积物抗性与主要由鱼粉中营养物质驱动的微生物群落结构（P<0.05）显著相关。综上所述，我们的研究结果表明，鱼粉比四环素在海水养殖沉积物中的ARGs增殖中发挥更重要的作用。这项研究可能为减缓海水养殖作业中ARG的繁殖提供新的见解。

        Mariculture sediment has been recognized as a major contributor of environmental antibiotic resistance genes (ARGs), which are challenging the treatment of infections worldwide. Both antibiotics and fishmeal are used in aquaculture, and each has the potential to facilitate ARG dissemination, however their combined impact on the sediment resistome and their relative contribution remain unclear. In this study, microcosms were exposed to varying concentrations of tetracycline with or without fishmeal (0.1% wt/wt) for 14 days. Sediment genomic DNA was analyzed using high throughput quantitative PCR and 16S rRNA gene amplicon sequencing to compare the contribution of fishmeal and tetracycline to antibiotic resistomes and bacterial communities in mariculture sediment. Sixty-seven ARGs were detected potentially correlating to resistance for several major antibiotics. Fishmeal, but not the dose of tetracycline, contributed to the significant increase of both ARG abundance and diversity in the sediment. Based on principle coordinate analysis and hierarchical clustering, ARGs were clustered into two groups depending on whether fishmeal was added. Aminoglycoside, macrolide-lincosamide-streptogramin b (MLSb) and tetracycline resistance genes were the most abundant when fishmeal was used, while a significant increase in mobile genetic element (MGE) abundance was also detected (P < 0.05). Meanwhile, bacterial community structures were detected with distinct patterns between the two groups (Adonis, P < 0.05). Using the Mantel test and partial least squares path modeling, we identified that sediment resistomes were significantly correlated with microbial community structures (P < 0.05) which were mainly driven by nutrients in fishmeal. Together our findings suggested that fishmeal plays a more important role than tetracycline in proliferation of ARGs in mariculture sediment. This study may provide new insights into the mitigation of ARG propagation in mariculture operations.

       https://www.sciencedirect.com/science/article/pii/S0269749118314313?via%3Dihub