摘要

    在中国养猪场广泛使用的缺氧-缺氧（A / O）废水处理工艺是抗生素抗性基因（ARG）的重要储存库。但是，在A / O流程中ARG及其主机的分布尚未得到很好的描述。在这项研究中，从38个养猪场收集了用于A / O工艺的缺氧和有氧槽中的废水。研究了20种亚型ARG，5种反硝化相关基因，2种整合素和细菌群落组成的浓度。细菌基因组分级使用后基因组测序进行。在这项研究中，在所有采样位点检测到20种亚型的ARGs和整合素。在缺氧罐中，共检测到20种亚型ARGs中的16种，其丰度最高，而sul1的最大平均丰度为19.21±0.24 log10（份/ mL）。在猪场A / O过程中观察到某些基因的共现模式，例如sul1和intl1，sul1和tetG以及tetO和tetW。优势反硝化细菌与某些ARG（blaTEM，ermB，tetC，tetH和tetQ）之间存在明显的共现模式，因此优势反硝化细菌被认为是潜在的ARG宿主。此外，还组装了170个高度丰富的细菌基因组箱，并进一步证实反硝化细菌短螺旋体，念珠菌竞争杆菌，硫杆菌和类固醇细菌是养猪场A / O过程中的重要ARG宿主，为监测和风险管理提供了有用的参考猪场废水中的ARGs含量。

    The anoxic-oxic (A/O) wastewater treatment process that is widely used in pig farms in China is an important repository for antibiotic resistance genes (ARGs). However, the distribution of ARGs and their hosts in the A/O process has not been well characterized. In this study, the wastewaters in the anoxic and oxic tanks for A/O processes were collected from 38 pig farms. The concentrations of 20 subtypes of ARGs, 5 denitrification-related genes, 2 integrons, and bacterial community composition were investigated. Bacterial genome binning was performed using metagenome sequencing. In this study, 20 subtypes of ARGs and integrons were detected in all sampling sites. A total of 16 of the 20 subtypes of ARGs were detected with the highest abundance in anoxic tanks, and sul1 was detected with a maximum average abundance of 19.21 ± 0.24 log10 (copies/mL). Cooccurrence patterns were observed for some genes in the pig farm A/O process, such as sul1 and intl1, sul1 and tetG, and tetO and tetW. There was a significant cooccurrence pattern between the dominant denitrifying bacteria and some ARGs (blaTEM, ermB, tetC, tetH and tetQ), so the dominant denitrifying bacteria were considered to be potential ARG hosts. In addition, 170 highly abundant bacterial genome bins were assembled and further confirmed that the denitrifying bacteria Brachymonas, Candidatus Competibacter, Thiobacillus and Steroidobacter were the important ARG hosts in the pig farm A/O process, providing a useful reference for the surveillance and risk management of ARGs in pig farm wastewater.

    https://www.sciencedirect.com/science/article/pii/S0160412020318523