Environmental Microbiology and Ecology Research Center, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Science, Chongqing 400714, China; University of Chinese Academy of Sciences, Beijing 101407, China.
Departments of Geology & Geophysics, University of Utah, Salt Lake City, UT 84112, USA.
Sci Total Environ. 2018 Sep 1;634:1231-1237. doi: 10.1016/j.scitotenv.2018.04.048. Epub 2018 Apr 18.
Landfill is important reservoirs of residual antibiotics and antibiotic resistance genes (ARGs), but the mechanism of landfill application influence on antibiotic resistance remains unclear. Although refuse decomposition plays a crucial role in landfill stabilization, its impact on the antibiotic resistance has not been well characterized. To better understand the impact, we studied the dynamics of ARGs and the bacterial community composition during refuse decomposition in a bench-scale bioreactor after long term operation (265d) based on metagenomics analysis. The total abundances of ARGs increased from 431.0ppm in the initial aerobic phase (AP) to 643.9ppm in the later methanogenic phase (MP) during refuse decomposition, suggesting that application of landfill for municipal solid waste (MSW) treatment may elevate the level of ARGs. A shift from drug-specific (bacitracin, tetracycline and sulfonamide) resistance to multidrug resistance was observed during the refuse decomposition and was driven by a shift of potential bacteria hosts. The elevated abundance of Pseudomonas mainly contributed to the increasing abundance of multidrug ARGs (mexF and mexW). Accordingly, the percentage of ARGs encoding an efflux pump increased during refuse decomposition, suggesting that potential bacteria hosts developed this mechanism to adapt to the carbon and energy shortage when biodegradable substances were depleted. Overall, our findings indicate that the use of landfill for MSW treatment increased antibiotic resistance, and demonstrate the need for a comprehensive investigation of antibiotic resistance in landfill.
垃圾填埋场是残留抗生素和抗生素抗性基因（ARGs）的重要储存库，但填埋场应用如何影响抗生素抗性的机制仍不清楚。尽管垃圾分解在填埋场稳定化中起着至关重要的作用，但它对抗生素抗性的影响尚未得到很好的描述。为了更好地了解这种影响，我们通过宏基因组分析，研究了长期运行（265d）后，在一个基于实验室规模的生物反应器中，垃圾分解过程中 ARGs 和细菌群落组成的动态变化。在垃圾分解过程中，ARGs 的总丰度从初始好氧阶段（AP）的 431.0ppm 增加到后期产甲烷阶段（MP）的 643.9ppm，这表明填埋场应用于城市固体废物（MSW）处理可能会提高 ARGs 的水平。在垃圾分解过程中，从特定药物（杆菌肽、四环素和磺胺类药物）抗性向多药抗性的转变，是由潜在细菌宿主的转变驱动的。假单胞菌丰度的升高主要导致多药 ARGs（mexF 和 mexW）的丰度增加。相应地，在垃圾分解过程中，编码外排泵的 ARGs 的百分比增加，表明当可生物降解物质耗尽时，潜在的细菌宿主可能发展了这种机制来适应碳源和能量的短缺。总的来说，我们的研究结果表明，垃圾填埋场用于处理城市固体废物会增加抗生素抗性，并表明需要对填埋场中的抗生素抗性进行全面调查。
