Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Science, China Agriculture University, Beijing, 100193, China.
Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan, 571101, China.
J Environ Manage. 2023 Nov 1;345:118651. doi: 10.1016/j.jenvman.2023.118651. Epub 2023 Jul 25.
Organic solid wastes (OSWs) are important reservoirs for antibiotic resistance genes (ARGs). Aerobic composting transforms OSWs into fertilizers. In this study, we investigated ARGs dynamics and their driving mechanisms in three OSW composts: pig manure (PM), kitchen waste (KC), and sewage sludge (SG). The dominant ARGs were different in each OSW, namely tetracycline, aminoglycoside, and macrolide resistance (PM); tetracyclines and aminoglycosides (KC); and sulfonamides (SG). ARGs abundance decreased in PM (71%) but increased in KC (5.9-fold) and SG (1.3-fold). Interestingly, the ARGs abundance was generally similar in all final composts, which was contributed to the similar bacterial community in final composts. In particular, sulfonamide and β-lactam resistant genes removed (100%) in PM, while sulfonamide in KC (38-fold) and tetracycline in SG (5-fold) increased the most. Additionally, ARGs abundance rebounded during the maturation period in all treatments. Firmicutes, Proteobacteria, and Actinobacteria were the main ARGs hosts. Several persistent and high-risk genes included tetW, aadA, aadE, tetX, strB, tetA, mefA, intl1, and intl2. The structural equation models showed ARGs removal was mainly affected by physicochemical parameters and bacterial communities in PM, the ARGs enrichment in KC composting correlated with increased mobile genetic elements (MGEs). In general, thermophilic aerobic composting can inhibit the vertical gene transfer (VGT) of pig manure and horizontal gene transfer (HGT) of sludge, but it increases the HGT of kitchen waste, resulting in a dramatic increase of ARGs in KC compost. More attention should be paid to the ARGs risk of kitchen waste composting.
有机固体废物（OSW）是抗生素抗性基因（ARGs）的重要储存库。好氧堆肥将 OSW 转化为肥料。在这项研究中，我们研究了三种 OSW 堆肥（猪粪（PM）、厨余垃圾（KC）和污水污泥（SG））中 ARGs 的动态及其驱动机制。每种 OSW 中的优势 ARGs 不同，即四环素、氨基糖苷类和大环内酯类抗性（PM）；四环素和氨基糖苷类（KC）；和磺胺类（SG）。ARGs 丰度在 PM 中减少（71%），但在 KC（增加 5.9 倍）和 SG（增加 1.3 倍）中增加。有趣的是，所有最终堆肥中的 ARGs 丰度通常相似，这归因于最终堆肥中相似的细菌群落。特别是，PM 中去除了磺胺类和β-内酰胺类抗性基因（100%），而 KC 中的磺胺类（38 倍）和 SG 中的四环素类（5 倍）增加最多。此外，在所有处理中，ARGs 丰度在成熟期间都有反弹。厚壁菌门、变形菌门和放线菌门是主要的 ARGs 宿主。一些持久性和高风险基因包括 tetW、aadA、aadE、tetX、strB、tetA、mefA、intl1 和 intl2。结构方程模型表明，ARGs 的去除主要受 PM 中的理化参数和细菌群落的影响，KC 堆肥中 ARGs 的富集与移动遗传元件（MGEs）的增加有关。总的来说，高温好氧堆肥可以抑制猪粪的垂直基因转移（VGT）和污泥的水平基因转移（HGT），但会增加厨余垃圾的 HGT，导致 KC 堆肥中 ARGs 的急剧增加。应该更加关注厨余垃圾堆肥的 ARGs 风险。
