College of Resources and Environment, Southwest University, Chongqing 400715, China.
College of Resources and Environment, Southwest University, Chongqing 400715, China.
Sci Total Environ. 2022 Dec 20;853:158667. doi: 10.1016/j.scitotenv.2022.158667. Epub 2022 Sep 10.
Tetracyclines (TCs) are one of the most widely used antibiotics in livestock and poultry industry. Sichuan province and Chongqing city are the provinces and cities with the most concentrated purple soil distribution in China, as well as the largest livestock and poultry breeding scale. Purple soils with low organic carbon content and poor structure, and manure fertilizers were heavily applied to improve soil quality. However, the research on antibiotic resistance genes (ARGs) dispersal in purple soils is limited. Overall, 234 ARGs subtypes belonging to 15 types were detected in all soils. Long-term application of livestock manures significantly changed the characteristics of ARGs, mobile genetic elements (MGEs), pathogen species and bacterial communities in the soil, and increased by 103.2 %, 13.1 %, 188.6 % and 43.7 % in chicken manure treatments compared with the control, respectively. Partial equation PLS-PM analysis further reveals that the main driving factor of ARGs is bacterial abundance, while bacterial diversity has a negative effect on ARGs abundance. Through ANOVA and network analysis, it was found that 30 ARGs were significantly affected by manure, its relative abundance is 0.8-1.4 times that of the control treatment. The qPCR results also proved that the relative abundance of ARGs including sul2, etc. increased with the increase of manure application and these resistance genes in chicken manure treatments were higher than in pig manure treatments. These resistance genes pose a high risk to public health, and chicken manure application posed a higher risk than pig manure. The TC content in the 40-60 cm soil layer was higher in medium- and high-volume pig manure, which was at risk of being transported to groundwater. Our research results deepen the understanding of ARGs transmission in purple soil under agricultural activities and emphasize the species and distribution of antibiotic resistance genes may differ across soil and manure types.
四环素（TCs）是畜牧业和家禽养殖业中使用最广泛的抗生素之一。四川省和重庆市是中国紫色土分布最集中、畜牧业和家禽养殖规模最大的省份和城市。紫色土有机碳含量低、结构差，施用大量粪肥来改善土壤质量。然而，有关抗生素抗性基因（ARGs）在紫色土壤中传播的研究有限。总的来说，在所有土壤中检测到属于 15 种类型的 234 种 ARG 亚型。长期施用牲畜粪便显著改变了土壤中 ARGs、移动遗传元件（MGEs）、病原体种类和细菌群落的特征，与对照相比，鸡粪处理分别增加了 103.2%、13.1%、188.6%和 43.7%。偏最小二乘偏最小二乘法（PLS-PM）分析进一步揭示，ARGs 的主要驱动因素是细菌丰度，而细菌多样性对 ARGs 丰度有负效应。通过方差分析和网络分析，发现 30 种 ARGs 受到粪便的显著影响，其相对丰度是对照处理的 0.8-1.4 倍。qPCR 结果也证明了包括 sul2 在内的 ARGs 的相对丰度随着粪肥施用量的增加而增加，而且鸡粪处理中的这些抗性基因高于猪粪处理。这些抗性基因对公众健康构成高风险，鸡粪的应用比猪粪的应用风险更高。中高剂量猪粪在 40-60cm 土层中的 TC 含量较高，有向地下水迁移的风险。我们的研究结果加深了对农业活动下紫色土中 ARGs 传播的认识，并强调抗生素抗性基因的种类和分布可能因土壤和粪肥类型而异。
