摘要

        全球每年产生约 13 亿吨食物垃圾 (FW)。大部分 FW 被沉积到垃圾填埋场，从而导致环境污染和温室气体排放。虽然在工业规模的堆肥中越来越多的 FW 被更可持续地回收到肥料中，但对 FW 中存在的抗生素抗性基因 (ARG) 以及它们的丰度如何受到堆肥的影响知之甚少。为了研究这一点，我们量化了 FW 堆肥开始、期间和结束时 ARG、移动遗传元件 (MGE) 和细菌群落的多样性和丰度。在每个样品中都检测到所有靶向的 27 个 ARG 和 5 个 MGE，表明堆肥 FW 仍然是 ARG 和 MGE 的储存库。虽然堆肥极大地改变了细菌群落的丰度、组成和多样性，但观察到总 ARG 和 MGE 丰度增加。 Procrustes 分析显示，ARG 的变化与细菌群落组成的变化有关（P<0.01）。至关重要的是，即使高堆肥温度降低了最初与 ARG 相关的细菌类群的丰度和多样性，但在其他相关的细菌类群中仍保持着 ARG 丰度。这可能是由水平基因转移和物理化学堆肥特性驱动的，正如 ARG、MGE、pH、NO3-和水分之间明显的正相关所揭示的那样。我们的研究结果表明，传统堆肥在从 FW 中去除 ARG 和 MGE 方面效率不高。因此需要更有效的堆肥策略，以尽量减少从堆肥 FW 释放到农业环境中的 ARG。

       About 1.3 billion tons of food waste (FW) is annually produced at a global scale. A major fraction of FW is deposited into landfills thereby contributing to environmental pollution and emission of greenhouse gasses. While increasing amounts of FW are recycled more sustainably into fertilizers in industrial-scale composting, very little is known about the antibiotic resistance genes (ARGs) present in FW and how their abundance is affected by composting. To study this, we quantified the diversity and abundance of ARGs, mobile genetic elements (MGEs) and bacterial communities in the beginning, during and at the end of the FW composting. All targeted 27 ARGs and 5 MGEs were detected in every sample suggesting that composted FW remains a reservoir of ARGs and MGEs. While the composting drastically changed the abundance, composition and diversity of bacterial communities, an increase in total ARG and MGE abundances was observed. Changes in ARGs were linked with shifts in the composition of bacterial communities as revealed by a Procrustes analysis (P < 0.01). Crucially, even though the high composting temperatures reduced the abundance and diversity of initially ARG-associated bacterial taxa, ARG abundances were maintained in other associated bacterial taxa. This was likely driven by horizontal gene transfer and physicochemical composting properties as revealed by a clear positive correlation between ARGs, MGEs, pH, NO3− and moisture. Together our findings suggest that traditional composting is not efficient at removing ARGs and MGEs from FW. More effective composting strategies are thus needed to minimize ARG release from composted FW into agricultural environments.

https://www.sciencedirect.com/science/article/abs/pii/S004896971835246X