Department of Environmental Chemistry, IDAEA-CSIC, C/Jordi Girona, 18-26, 08034, Barcelona, Spain.
Department of Hydrosciences, Technische Universität Dresden, Dresden, Germany.
Environ Res. 2019 Oct;177:108608. doi: 10.1016/j.envres.2019.108608. Epub 2019 Jul 26.
Despite the social concern about the generalization of antibiotic resistance hotspots worldwide, very little is known about the contribution of different potential sources to the global risk. Here we present a quantitative analysis of the distribution of Antibiotic Resistance Genes (ARGs) in soil, rhizospheric soil, roots, leaves and beans in tomato, lettuce and broad beans crops (165 samples in total), grown in nine commercial plots distributed in four geographical zones in the vicinity of Barcelona (North East Spain). We also analyzed five soil samples from a nearby forest, with no record of agricultural activities. DNA samples were analyzed for their content in the ARGs sul1, tetM, qnrS1, bla, bla, mecA, and bla, plus the integron intI1, using qPCR methods. In addition, soil microbiomes from the different plots were analyzed by amplicon-targeted 16S rRNA gene sequencing. Our data show a decreasing gradient of ARG loads from soil to fruits and beans, the latter showing only from 0.1 to 0.01% of the abundance values in soil. The type of crop was the main determinant for both ARG distribution and microbiome composition among the different plots, with minor contributions of geographic location and irrigation water source. We propose that soil amendment and/or fertilization, more than irrigation water, are the main drivers of ARG loads on the edible parts of the crop, and that they should therefore be specifically controlled.
尽管全球社会普遍关注抗生素耐药性热点的扩散，但对于不同潜在来源对全球风险的贡献，人们知之甚少。在这里，我们对番茄、生菜和蚕豆作物（共 165 个样本）中土壤、根际土壤、根、叶和豆中的抗生素耐药基因（ARGs）分布进行了定量分析，这些作物生长在巴塞罗那附近四个地理区域的九个商业地块中。我们还分析了附近森林中的五个土壤样本，这些样本没有农业活动的记录。使用 qPCR 方法分析了 DNA 样本中 sul1、tetM、qnrS1、bla、bla、mecA 和 bla 基因以及整合子 intI1 的含量。此外，还通过扩增子靶向 16S rRNA 基因测序分析了不同地块的土壤微生物组。我们的数据表明，从土壤到果实和豆类，ARGs 负荷呈递减梯度，后者在土壤中的丰度值仅为 0.1%至 0.01%。作物类型是决定不同地块中 ARG 分布和微生物组组成的主要因素，地理位置和灌溉水源的影响较小。我们提出，土壤改良和/或施肥，而不是灌溉水，是作物可食用部分 ARG 负荷的主要驱动因素，因此应专门加以控制。
