摘要
      四环素类抗生素是畜禽养殖业中应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的省市，也是畜禽养殖规模最大的省市。有机碳含量低、结构差的紫色土壤，大量施用肥料以改善土壤质量。然而，关于抗生素抗性基因（ARGs）在紫色土壤中传播的研究是有限的。总体而言，在所有土壤中检测到属于15种类型的234种ARGs亚型。长期施用畜禽粪肥显著改变了土壤中ARGs、移动遗传元素、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%。偏方程PLS-PM分析进一步揭示了ARGs的主要驱动因素是细菌丰度，而细菌多样性对ARGs丰度有负面影响。通过方差分析和网络分析发现，30个ARGs受到粪肥的显著影响，其相对丰度是对照处理的0.8–1.4倍。qPCR结果还证明，包括sul2等在内的ARGs的相对丰度随着施肥量的增加而增加，并且这些抗性基因在鸡粪处理中高于在猪粪处理中。这些抗性基因对公众健康构成高风险，施用鸡粪的风险高于施用猪粪的风险。40–60厘米土层中的TC含量在中等和高容量猪粪中较高，有被输送到地下水的风险。我们的研究结果加深了对农业活动下ARGs在紫色土壤中传播的理解，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。
Abstract
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.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722057667