Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing, 210098, PR China.
Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing, 210098, PR China.
J Environ Manage. 2024 Nov;370:122661. doi: 10.1016/j.jenvman.2024.122661. Epub 2024 Sep 26.
Antibiotic resistance is a growing environmental issue. As a sink for antibiotic resistance genes (ARGs), lake surface sediments are well known for the spread of ARGs. However, the distribution pattern of ARGs and their relationship with environmental factors in vertical sediment layers are unclear. In this study, we investigated the resistome distribution in sediment cores from Taihu Lake using metagenomic analysis. The results showed that the abundance of total ARGs increased by 153% as the sediment depth rose from 0 to 50 cm, and the ARG Shannon index significantly increased. Among all the ARG types, efflux pump genes (e.g., mexT and mexW) were dominant, especially in 40-50 cm sediment. The variation in ARG with depth described above was related to the changes in bacterial adaptation to environmental gradients. Specifically, sulfate and nitrate concentrations decreased with depth, and random forest analysis showed that they were the main factors affecting the changes in ARG abundance. Environmental factors were also found to indirectly impact the distribution of ARGs by affecting the bacterial community. Potential sulfate-reducing gene/nitrate-reducing gene-ARG co-hosts were annotated through metagenomic assembly. The dominant co-hosts, Curvibacter, and Comamonas, which were enriched in deeper sediments, may have contributed to the enrichment of ARGs in deep sediments. Overall, our findings demonstrated that bacterial-mediated sulfate and nitrate reduction was closely related to sediment resistance, which provided new insights into the control of antibiotic resistance.
抗生素耐药性是一个日益严重的环境问题。作为抗生素耐药基因（ARGs）的汇，湖泊表层沉积物因 ARGs 的传播而广为人知。然而，ARGs 在垂直沉积物层中的分布模式及其与环境因素的关系尚不清楚。在这项研究中，我们使用宏基因组分析研究了太湖沉积物岩芯中的耐药组分布。结果表明，随着沉积物深度从 0 到 50cm 的增加，总 ARG 的丰度增加了 153%，ARG Shannon 指数显著增加。在所有的 ARG 类型中，外排泵基因（如 mexT 和 mexW）占主导地位，尤其是在 40-50cm 的沉积物中。上述 ARG 随深度的变化与细菌对环境梯度的适应变化有关。具体来说，硫酸盐和硝酸盐浓度随深度降低，随机森林分析表明它们是影响 ARG 丰度变化的主要因素。环境因素也通过影响细菌群落间接影响 ARG 的分布。通过宏基因组组装注释了潜在的硫酸盐还原基因/硝酸盐还原基因-ARG 共宿主。丰度较高的共宿主弯曲杆菌和贪噬菌，在较深的沉积物中富集，可能导致 ARGs 在深沉积物中富集。总的来说，我们的研究结果表明，细菌介导的硫酸盐和硝酸盐还原与沉积物耐药性密切相关，为控制抗生素耐药性提供了新的见解。
