摘要

       牲畜粪便经常进行好氧堆肥，但在不同浓度抗生素下堆肥过程中抗生素抗性基因 (ARG) 的变化知之甚少。本研究比较了三种浓度的土霉素（OTC；10、60 和 200 mg/kg）对 ARG 和堆肥过程中细菌群落演替的影响。在堆肥过程中，在 OTC 处理和对照之间，在每个 ARG 的相对丰度 (RA) 中观察到非常相似的趋势。堆肥后，tetC、tetX、sul1、sul2 和 intI1 的 RA 增加了 2-43 倍，而 tetQ、tetM 和 tetW 的 RA 下降了 44-99%。 OTC 添加显着增加了 tetC 和 intI1 的绝对丰度和 RA，而 200 mg/kg OTC 也增强了 tetM、tetQ 和 drfA7 的绝对丰度和 RA。细菌群落可以根据不同处理下的堆肥时间进行分组。最高浓度的 OTC 对细菌群落具有更持久的影响。在本研究中，与抗生素的存在相比，细菌群落的演替似乎对堆肥过程中 ARG 的变化具有更大的影响。好氧堆肥不能有效减少大部分 ARGs，因此堆肥产品应被视为 ARGs 的重要储存库。

       Livestock manure is often subjected to aerobic composting but little is known about the variation in antibiotic resistance genes (ARGs) during the composting process under different concentrations of antibiotics. This study compared the effects of three concentrations of oxytetracycline (OTC; 10, 60, and 200 mg/kg) on ARGs and the succession of the bacterial community during composting. Very similar trends were observed in the relative abundances (RAs) of each ARG among the OTC treatments and the control during composting. After composting, the RAs of tetC, tetX, sul1, sul2, and intI1 increased 2–43 times, whereas those of tetQ, tetM, and tetW declined by 44–99%. OTC addition significantly increased the absolute abundances and RAs of tetC and intI1, while 200 mg/kg OTC also enhanced those of tetM, tetQ, and drfA7. The bacterial community could be grouped according to the composting time under different treatments. The highest concentration of OTC had a more persistent effect on the bacterial community. In the present study, the succession of the bacterial community appeared to have a greater influence on the variation of ARGs during composting than the presence of antibiotics. Aerobic composting was not effective in reducing most of the ARGs, and thus the compost product should be considered as an important reservoir for ARGs.

https://www.sciencedirect.com/science/article/abs/pii/S0304389416304216