摘要

       通过施用肥料，对抗生素产生抗药性的细菌基因从牲畜传播到土壤，威胁环境和人类健康。我们研究了ARG的传播和持久性机制，以解开i）营养物质和微生物对土壤四环素（TET）抵抗力组的影响，以及ii）土著土壤微生物群在防止ARG扩散中的作用。我们分析了短期（7天）和持久（84天）肥料对三种不含抗生素的牧场土壤抵抗力的影响。评估了四种微观处理：对照，矿物养分施肥以及在土壤或经γ辐照的土壤上沉积一层新鲜肥料。我们量化了五个抗TET的基因，分离了135个抗TET的细菌，并对可培养的抗TET的细菌和整个细菌进行了测序。改良粪肥而不增加养分可以增加TET-r基因（例如tet（Y））的丰度。与耐TET的细菌组成相反，这种变化随时间持续存在，在粪肥改良后部分恢复。施用肥料的γ辐照土壤比未辐照的土壤显着降低了养分含量，并提高了TET-r基因丰度，这表明天然土壤细菌对于肥料对土壤的施肥作用以及控制潜在危险的TET-r的传播至关重要。基因。

       Bacterial genes responsible for resistance to antibiotic agents (ARG) are spread from livestock to soil through application of manure, threatening environmental and human health. We investigated the mechanisms of ARG dissemination and persistence to disentangle i) the influence of nutrients and microorganisms on the soil tetracycline (TET) resistome, and ii) the role of indigenous soil microbiota in preventing ARG spread. We analysed short-term (7 days) and persistent (84 days) effects of manure on the resistome of three antibiotic-free pasture soils. Four microcosm treatments were evaluated: control, mineral nutrient fertilization, and deposition of a layer of fresh manure onto soil or γ-irradiated soil. We quantified five TET-resistance genes, isolated 135 TET-resistant bacteria and sequenced both culturable TET-resistant and whole bacterial communities. Manure amendments, but not nutrient addition, increased the abundance of TET-r genes such as tet(Y). Such changes persisted with time, in contrast with the TET-resistant bacterial composition, which partially recovered after manure amendments. Manured γ-irradiated soils showed significantly lower nutrient content and higher TET-r gene abundance than non-irradiated soils, suggesting that native soil bacteria are essential for the fertilization effect of manure on soil as well as control the dissemination of potentially risky TET-r genes.

        https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6494816/