Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China; National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China; Key Laboratory of Tropical Agricultural Environment, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China; National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China; Key Laboratory of Tropical Agricultural Environment, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China; Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, South China Agriculture University, Guangzhou 510642, China.
Environ Int. 2020 Oct;143:105897. doi: 10.1016/j.envint.2020.105897. Epub 2020 Jun 29.
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 log (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 (bla, 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.
在中国，广泛应用于猪场的缺氧-好氧（A/O）废水处理工艺是抗生素抗性基因（ARGs）的重要储存库。然而，A/O 工艺中 ARGs 及其宿主的分布尚未得到很好的描述。在这项研究中，从 38 个猪场收集了缺氧池和好氧池的 A/O 工艺废水。调查了 20 种抗生素抗性基因亚型、5 种硝化相关基因、2 种整合子和细菌群落组成。使用宏基因组测序进行细菌基因组分类。在本研究中，所有采样点均检测到 20 种抗生素抗性基因亚型和整合子。20 种抗生素抗性基因亚型中有 16 种在缺氧池中检测到最高丰度，sul1 的平均丰度最高，为 19.21±0.24 log (copies/mL)。在猪场 A/O 工艺中观察到一些基因的共现模式，如 sul1 和 intl1、sul1 和 tetG 以及 tetO 和 tetW。在优势脱氮菌和一些 ARGs（bla、ermB、tetC、tetH 和 tetQ）之间存在显著的共现模式，因此，优势脱氮菌被认为是潜在的 ARG 宿主。此外，组装了 170 个高丰度的细菌基因组分类，进一步证实了脱氮菌 Brachymonas、Candidatus Competibacter、Thiobacillus 和 Steroidobacter 是猪场 A/O 工艺中重要的 ARG 宿主，为猪场废水 ARGs 的监测和风险管理提供了有用的参考。
