摘要

       堆肥被认为是通过施用有机肥减少抗微生物基因（ARGs）在环境中的导入，但目前还不清楚ARGs对堆肥植物大气环境可能造成的污染。在这项研究中，我们收集了4个堆肥厂的29个空气样本，包括上下风、堆肥、包装和办公区。分别采用液滴数字PCR和16srrna基因测序技术，对22种ARGs亚型、1类整合子（intl1）和2种潜在人类病原菌（HPB）及细菌群落进行了动态检测。本研究在堆肥区、包装区、办公区和下风区的空气中检测到除tetQ外的intl1和22种ARGs亚型。22种ARGs亚型中，15种在包装区检测到最高浓度，intl1的最高平均浓度为104 份/m3，最高为（1.78    0.49） × 10-2份/16srrna份。ARGs、潜在HPBs和细菌组分的非量度多维标度均表明，包装区的生物气溶胶污染模式与堆肥区最为相似，其次是办公区、下风区和上风区。通过Procrustes试验、mantel试验和网络分析评价了ARGs与细菌类群的共现性，结果表明，堆肥区和包装区的ARG碎片对办公区和下风区ARG气溶胶的组成有贡献。结果表明，堆肥植物的大气环境中含有丰富多样的arg，这就迫切需要对堆肥生产和土地利用过程中潜在的人体健康和生态风险进行综合评价。

       Composting is considered to reduce the introduction of antimicrobial resistance genes (ARGs) into the environment through land application of manure; however, the possible pollution of ARGs in the atmospheric environment of composting plants is unknown. In this study, 29 air samples including up- and downwind, composting, packaging, and office areas from 4 composting plants were collected. Dynamic concentrations of 22 subtypes of ARGs, class 1 integron (intl1), and 2 potential human pathogenic bacteria (HPB), and bacterial communities were investigated using droplet digital PCR and 16S rRNA gene sequencing, respectively. In this study, intl1 and 22 subtypes of ARGs (except tetQ) were detected in air of composting, packaging, office, and downwind areas. The highest concentration of 15 out of 22 subtypes of ARGs was detected in the packaging areas, and intl1 also had the maximum average concentration of 10⁴ copies/m³, with up to (1.78 ± 0.49) × 10^-2 copies/16S rRNA copy. Non-metric multi-dimensional scaling of ARGs, potential HPBs, and bacterial components all indicated that the bioaerosol pollutant pattern in packaging areas was most similar to that in composting areas, followed by office, downwind, and upwind areas. The co-occurrence between ARGs and bacterial taxa assessed by Procrustes test, mantel test, and network analysis implied that aerosolized ARG fragments from composting and packaging areas contributed to the compositions of ARG aerosols in office and downwind areas. The results presented here show that atmoshperic environments of composting plants harbor abundant and diverse ARGs, which highlight the urgent need for comprehensive evaluation of potential human health and ecological risks of composts during both production as well as land application.

        https://www.sciencedirect.com/science/article/pii/S0160412018301284?via%3Dihub