摘要

沼气厂的消化残渣常被用作农作物栽培的生物肥料。消化残余物中的抗生素抗性基因( ARGs )由于其潜在传播到致病微生物中而对公共健康构成高风险，从而降低了致病微生物在医疗中对抗生素的敏感性。本研究采用高通量测序( HTS )宏基因组学方法，研究了全规模沼气反应器中ARGs的变化及其与微生物群落和金属抗性基因( MRGs )的相关性。所有样品中ARG的总丰度不等，在ARGs/ 16S - rRNA基因拷贝7×10 - 3～1.08×10 - 1拷贝之间，从高温沼气反应器获得的样品中ARG的总丰度较低，说明高温厌氧消化去除ARG的优越性。所有样本中的ARG均由175个ARG亚型组成；然而，所有样本仅有7个ARG亚型。主成分分析和典型对应分析将样品分为三组(基于粪肥的嗜温反应器，基于肥料的嗜热反应器和基于污泥的嗜温反应器)，确定底物、温度、水力停留时间( HRT )和挥发性脂肪酸( VFAs )是影响ARGs组成的关键环境变量。procrustes分析表明，微生物群落组成是决定沼气反应器中ARGs组成的决定因素，ARGs组成与MRGs组成之间也存在显著的相关性。网络分析进一步揭示了ARGs与特定微生物和MRGs的共同存在。

Digested residues from biogas plants are often used as biofertilizers for agricultural crops cultivation. The antibiotic resistance genes (ARGs) in digested residues pose a high risk to public health due to their potential spread to the disease-causing microorganisms and thus reduce the susceptibility of disease-causing microorganisms to antibiotics in medical treatment. A high-throughput sequencing (HTS)-based metagenomic approach was used in the present study to investigate the variations of ARGs in full-scale biogas reactors and the correlations of ARGs with microbial communities and metal resistance genes (MRGs). The total abundance of ARGs in all the samples varied from 7 × 10–3 to 1.08 × 10–1 copy of ARG/copy of 16S-rRNA gene, and the samples obtained from thermophilic biogas reactors had a lower total abundance of ARGs, indicating the superiority of thermophilic anaerobic digestion for ARGs removal. ARGs in all the samples were composed of 175 ARG subtypes; however, only 7 ARG subtypes were shared by all the samples. Principal component analysis and canonical correspondence analysis clustered the samples into three groups (samples from manure-based mesophilic reactors, manure-based thermophilic reactors, and sludge-based mesophilic reactors), and substrate, temperature, and hydraulic retention time (HRT) as well as volatile fatty acids (VFAs) were identified as crucial environmental variables affecting the ARGs compositions. Procrustes analysis revealed microbial community composition was the determinant of ARGs composition in biogas reactors, and there was also a significant correlation between ARGs composition and MRGs composition. Network analysis further revealed the co-occurrence of ARGs with specific microorganisms and MRGs.

https://pubs.acs.org/doi/abs/10.1021/acs.est.6b05100