Zhang Yue, Song Ke, Zhang Juanqin, Xu Xiaoyun, Ye Geng, Cao Huan, Chen Ming, Cai Shumei, Cao Xinde, Zheng Xianqing, Lv Weiguang
Institute of Eco-Environment and Plant Protection, Shanghai Academy of Agricultural Sciences, Shanghai 201403, China.
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Sci Total Environ. 2022 Dec 10;851(Pt 1):158075. doi: 10.1016/j.scitotenv.2022.158075. Epub 2022 Aug 17.
Vermiremediation, which use earthworms to remove contaminants from soil, has been proven to be an alternative, low-cost technology. However, the effects of earthworm activity, especially the degraders in earthworm intestines, on the fate of sulfamethoxazole (SMX), and the effects of intestinal bacteria on degrading bacteria in soil are unclear. In this study, the effects of earthworms on the fate of SMX and related antibiotic resistance genes (ARGs) were investigated. Special attention was paid to the impact of earthworms on SMX degradation efficiency, degradation products, related ARGs, and degraders in both soil and earthworm intestines; the effect of intestinal bacteria on soil bacteria associated with SMX was also studied. Earthworms significantly accelerated SMX degradation by both intestinal detoxification and the stimulation of indigenous soil bacteria. Compared with the treatment without earthworms, the treatment with earthworms reduced SMX residues by 25.1 %, 49.2 %, 35.7 %, 34.2 %, and 35.7 % on the 10th, 20th, 30th, 60th, and 90th days, respectively. Compared with those in soil (treated with earthworms), the SMX residues in wormcasts were further reduced by 12.2-29.0 % from the 2nd to the 20th day, producing some unique anaerobic degradation products that were distinct from those in the soil. In earthworm intestines, SMX degradation was enhanced by bacteria of the genera Microvirga, Sphingomonas, Methylobacterium, Bacillus, and Tumebacillus. All of these bacteria (except Bacillus spp.) entered and colonised the soil with wormcasts, further promoting SMX degradation. Additionally, earthworms removed a significant number of ARGs by increasing the fraction of potential SMX degraders and inhibiting the potential hosts of ARGs and int1. This study demonstrated that earthworms could remediate SMX-contaminated soil by enhancing the removal of SMX and ARGs.
利用蚯蚓从土壤中去除污染物的蚯蚓修复技术已被证明是一种低成本的替代技术。然而，蚯蚓活动，特别是蚯蚓肠道中的降解菌，对磺胺甲恶唑（SMX）归宿的影响，以及肠道细菌对土壤中降解菌的影响尚不清楚。在本研究中，研究了蚯蚓对SMX归宿及相关抗生素抗性基因（ARGs）的影响。特别关注了蚯蚓对土壤和蚯蚓肠道中SMX降解效率、降解产物、相关ARGs和降解菌的影响；还研究了肠道细菌对与SMX相关的土壤细菌的影响。蚯蚓通过肠道解毒和刺激土壤原生细菌显著加速了SMX的降解。与无蚯蚓处理相比，蚯蚓处理在第10天、20天、30天、60天和90天分别使SMX残留量降低了25.1%、49.2%、35.7%、34.2%和35.7%。与土壤（蚯蚓处理）中的SMX残留量相比，从第2天到第20天，蚓粪中的SMX残留量进一步降低了12.2%-29.0%，产生了一些与土壤中不同的独特厌氧降解产物。在蚯蚓肠道中，微小病毒属、鞘氨醇单胞菌属、甲基杆菌属、芽孢杆菌属和肿瘤杆菌属的细菌增强了SMX的降解。所有这些细菌（芽孢杆菌属除外）都随着蚓粪进入并定殖在土壤中，进一步促进了SMX的降解。此外，蚯蚓通过增加潜在SMX降解菌的比例并抑制ARGs和int1的潜在宿主，去除了大量ARGs。本研究表明，蚯蚓可以通过增强对SMX和ARGs的去除来修复受SMX污染的土壤。
