摘要

尽管社会对全世界的抗生素耐药性热点问题普遍存在担忧，但对于不同潜在来源对全球风险的贡献知之甚少。在这里，我们对土壤，根际土壤，番茄，莴苣和蚕豆作物（总共165个样品）中的土壤，根际土壤，根，叶和豆类（总共165个样品）中抗生素抗性基因（ARG）的分布进行了定量分析，分布在四个区域中的9个商业区中巴塞罗那（西班牙东北部）附近的地理区域。我们还分析了附近森林中的五种土壤样品，但没有农业活动记录。使用qPCR方法分析DNA样品中ARGs sul1，tetM，qnrS1，blaCTX-M-32，blaOXA-58，mecA和blaTEM以及整联子intI1中的含量。另外，通过以扩增子为靶标的16S rRNA基因测序分析了不同地块的土壤微生物。我们的数据显示，从土壤到水果和豆类的ARG负荷梯度下降，后者仅显示土壤中丰度值的0.1％至0.01％。作物类型是不同地块中ARG分布和微生物组组成的主要决定因素，地理位置和灌溉水源的贡献较小。我们建议，土壤改良和/或施肥（比灌溉水更重要）是农作物可食用部分上ARG负荷的主要驱动因素，因此应对其进行专门控制。

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, blaCTX-M-32, blaOXA-58, mecA, and blaTEM, 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.

https://www.sciencedirect.com/science/article/pii/S0013935119304050