Environmental Science & Engineering, Yangzhou University, Yangzhou, Jiangsu, PR China; College of Marine and Bio-Engineering, Yancheng Teachers University, Yancheng, Jiangsu, PR China.
Environmental Science & Engineering, Yangzhou University, Yangzhou, Jiangsu, PR China.
J Hazard Mater. 2017 Oct 15;340:213-220. doi: 10.1016/j.jhazmat.2017.07.015. Epub 2017 Jul 8.
In this work, a microcosm experiment was conducted to merely mimic thermophilic phase in aerobic composting with pig manures in order to explore: (i) the effect of thermophilic phase in composting on the abundances of tetracycline resistance genes (TRGs); and (ii) the impacts of the treated manures on the abundances of TRGs in soil. It was found that 4days of thermophilic process reduced the abundance of TRGs in pig manures by ∼1 lg unit compared to the samples without treatments, suggesting that other phases in composting may play significant roles in removal of TRGs. Once pig manures with thermophilic treatment were applied to soil, TRGs abundances decreased to the levels in unfertilized soil. With correlation analyses, it was concluded that pig manure derived tetracycline-resistant bacteria (TRB) and nutrients exerted different effects on TRGs abundances in soil. In conclusion, short-term thermophilic treatment cannot remove tetracycline resistance genes in pig manures but exhibits controlling effects on their accumulation and spread in soil. Nutrients enrichment in soil following manuring of treated pig manures, together with a large proportion of gram-positive TRB left in treated pig manures with less risk to TRGs spread, contributed to the controlling effects.
在这项工作中，进行了一项微宇宙实验，仅模拟好氧堆肥中高温阶段的猪粪，以探索：（i）堆肥中高温阶段对四环素抗性基因（TRGs）丰度的影响；（ii）处理后的粪便对土壤中 TRGs 丰度的影响。结果发现，与未经处理的样品相比，4 天的高温过程使猪粪中的 TRGs 丰度减少了约 1lg 单位，表明堆肥的其他阶段可能在去除 TRGs 方面发挥了重要作用。一旦经过高温处理的猪粪施用于土壤，TRGs 的丰度就会降低到未施肥土壤的水平。通过相关性分析，可以得出结论，猪粪中来源的四环素抗性细菌（TRB）和养分对土壤中 TRGs 丰度的影响不同。总之，短期高温处理不能去除猪粪中的四环素抗性基因，但对其在土壤中的积累和传播具有控制作用。处理后的猪粪施入土壤后，土壤中的养分丰富，以及处理后的猪粪中留下的革兰氏阳性 TRB 比例较大，对 TRGs 的传播风险较低，这有助于控制作用的发挥。
