摘要
      在气候变化时期，实践一种可持续、适应气候变化和生产性的农业形式至关重要。堆肥可能是一种可持续的肥料，它可以增加土壤的腐殖质、持水能力和养分含量。因此，它可以加强农业以应对气候变化的不利影响，特别是当它与生物炭额外结合时。为了获得足够数量的适合堆肥的材料，目前被视为废物的资源，如人类排泄物，可能是一个很有前途的选择。然而，必须考虑生产的堆肥对人类病原体、药物（如抗生素）和相关耐药基因的安全性。在这种情况下，我们研究了140天和154天的高温堆肥对人类排泄物和干厕所的锯末以及添加和不添加生物炭的秸秆和绿色插条的卫生化的影响。在堆肥过程的开始和结束时采集堆肥样本，并进行宏基因组分析，以评估微生物群落在堆肥过程中抗生素抗性基因（ARGs）和致病因子的命运。在所有样本中检测到潜在的ARGs对主要类别的抗生素产生耐药性，如β-内酰胺类抗生素、万古霉素、MLSB组、氨基糖苷类、四环素类和喹诺酮类。然而，从堆肥开始到结束，ARGs的相对丰度都有所下降。编码III型、IV型和VI型分泌系统的基因也发现了这一趋势，这些系统分别参与致病性、蛋白质效应物转运到真核细胞和细菌之间的水平基因转移。结果表明，在高温堆肥过程中，携带ARGs的潜在致病微生物的发生率下降。尽管如此，ARG水平并没有下降到定量PCR（qPCR）的检测极限以下。关于可接受的抗性基因水平的堆肥使用阈值尚待评估和确定。
Abstract
In times of climate change, practicing a form of sustainable, climate-resilient and productive agriculture is of primordial importance. Compost could be one form of sustainable fertilizer, which is increasing humus, water holding capacity, and nutrient contents of soils. It could thereby strengthen agriculture toward the adverse effects of climate change, especially when additionally combined with biochar. To get access to sufficient amounts of suitable materials for composting, resources, which are currently treated as waste, such as human excreta, could be a promising option. However, the safety of the produced compost regarding human pathogens, pharmaceuticals (like antibiotics) and related resistance genes must be considered. In this context, we have investigated the effect of 140- and 154-days of thermophilic composting on the hygienization of human excreta and saw dust from dry toilets together with straw and green cuttings with and without addition of biochar. Compost samples were taken at the beginning and end of the composting process and metagenomic analysis was conducted to assess the fate of antibiotic resistance genes (ARGs) and pathogenicity factors of the microbial community over composting. Potential ARGs conferring resistance to major classes of antibiotics, such as beta-lactam antibiotics, vancomycin, the MLSB group, aminoglycosides, tetracyclines and quinolones were detected in all samples. However, relative abundance of ARGs decreased from the beginning to the end of composting. This trend was also found for genes encoding type III, type IV, and type VI secretion systems, that are involved in pathogenicity, protein effector transport into eukaryotic cells and horizontal gene transfer between bacteria, respectively. The results suggest that the occurrence of potentially pathogenic microorganisms harboring ARGs declines during thermophilic composting. Nevertheless, ARG levels did not decline below the detection limit of quantitative PCR (qPCR). Thresholds for the usage of compost regarding acceptable resistance gene levels are yet to be evaluated and defined.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9009411/