Agricultural soils are important source and sink of antibiotic resistance genes (ARGs). However, little is known about the fate of ARGs in dryland soils, while its human exposure risks were seriously overlooked. Taking the northern Ningxia Plain as a case, this study explored the occurrence of ARGs and its relationship with mobile genetic elements (MGEs), pathogens, and environmental factors. Furthermore, the concentrations of airborne ARGs by soil wind erosion and the human exposure doses of soil ARGs were evaluated. The results showed the abundances of different regions ranged from 4.0 × 105 to 1.6 × 106 copies/g. Soil ARGs are driven by MGEs, but multiply impacted by soil properties, nutrition, and bacterial community. Vibrio metschnikovii, Acinetobacter schindleri, and Serratia marcescens are potential pathogenic hosts for ARGs. Further exploration revealed the concentration of ARGs loaded in dust by soil wind erosion reached more than 105 copies/m3, which were even higher than those found in sewage treatment plants and hospitals. Skin contact is the primary route of ARGs exposure, with a maximum dose of 24071.33 copies/kg/d, which is largely attributed to ARGs loaded in dust. This study bridged the gap on ARGs in dryland soils, and provided reference for human exposure risk assessment of soil ARGs.

中文翻译：

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旱地耕作土壤抗生素抗性基因的发生率及人类暴露风险——以宁夏平原北部为例


农业土壤是抗生素耐药基因 （ARG） 的重要来源和汇。然而，人们对 ARG 在旱地土壤中的命运知之甚少，而其人类暴露风险被严重忽视。本研究以宁夏平原北部为例，探讨了耐药基因的发生及其与移动遗传元件 （MGEs）、病原体和环境因子的关系。此外，还评估了土壤风蚀引起的空气传播 ARGs 浓度和土壤 ARGs 的人体暴露剂量。结果显示，不同区域的丰度范围从 4.0 × 105 到 1.6 × 106 拷贝/g。土壤 ARG 由 MGE 驱动，但会受到土壤特性、营养和细菌群落的成倍影响。Vibrio metschnikovii、Acinetobacter schindleri 和 Serratia marcescens 是 ARGs 的潜在致病宿主。进一步的勘探表明，土壤风蚀所载于灰尘中的耐药基因浓度达到 105 拷贝/立方米以上，甚至高于污水处理厂和医院中的耐药基因浓度。皮肤接触是 ARGs 暴露的主要途径，最大剂量为 24071.33 拷贝/kg/d，这主要归因于灰尘中装载的 ARGs。本研究弥合了旱地土壤 ARGs 的差距，为土壤 ARGs 的人类暴露风险评估提供了参考。