摘要

       为了评估抗生素抗性基因 (ARG) 的季节性分布并探索其在不同季节和不同系统中模式的原因，选择了两个废水处理系统并使用高通量 qPCR 进行分析。线性判别分析 (LDA) 效应大小 (LEfSe) 用于发现差异 ARG（生物标志物）并估计生物标志物的效应大小。我们发现流入和剩余污泥样品中 ARGs 的总绝对丰度没有明显的季节性波动，而冬季流出样品中的 ARGs 总绝对丰度与流入样品相比有所下降。 11 个差异丰富的 ARG（生物标记基因、BmG）（aadA5-02、aac-6-II、cmlA1-01、cmlA1-02、blaOXA10-02、aadA-02、tetX、aadA1、ereA、qacEΔ1-01 和 blaTEM）夏季样品中的 10 BmG（tet-32、tetA-02、aacC2、vanC-03、aac-6-I1、tetE、ermB、mefA、tnpA-07 和 sul2）在冬季样品中得到验证。根据16S rRNA基因测序，门水平的细菌相对丰度表现出出水（OW）的显着季节性变化，在科（或属）水平发现了生物标志物细菌（BmB）。聚球藻和vadinCA02在夏季为BmB，毛球菌、乳球菌、Pelosinus、Janthinobacterium、亚硝化单胞菌科和Sterolibacterium为冬季BmB。此外，BmB 与同一季节的 BmGs 具有良好的相关性，这表明细菌群落变化在季节性变化期间驱动了 ARGs 的不同分布，并且 LEfSe 是一种快速有效的方法，用于发现两个或多个类别之间显着不同的 ARGs 和细菌。总之，本研究证明了两个废水处理系统中 BmGs 和 BmB 的季节性变化。

To evaluate the seasonal distribution of antibiotic resistance genes (ARGs) and explore the reason for their patterns in different seasons and different systems, two wastewater treatment systems were selected and analyzed using high-throughput qPCR. Linear discriminant analysis (LDA) effect size (LEfSe) was used to discover the differential ARGs (biomarkers) and estimate the biomarkers’ effect size. We found that the total absolute abundances of ARGs in inflows and excess sludge samples had no obvious seasonal fluctuations, while those in winter outflow samples decreased in comparison with the inflow samples. Eleven differentially abundant ARGs (biomarker genes, BmGs) (aadA5-02, aac-6-II, cmlA1-01, cmlA1-02, blaOXA10-02, aadA-02, tetX, aadA1, ereA, qacEΔ1-01, and blaTEM) in summer samples and 10 BmGs (tet-32, tetA-02, aacC2, vanC-03, aac-6-I1, tetE, ermB, mefA, tnpA - 07, and sul2) in winter samples were validated. According to 16S rRNA gene sequencing, the relative abundance of bacteria at the phylum level exhibited significant seasonal changes in outflow water (OW), and biomarker bacteria (BmB) were discovered at the family (or genus) level. Synechococcus and vadinCA02 are BmB in summer, and Trichococcus, Lactococcus, Pelosinus, Janthinobacterium, Nitrosomonadaceae and Sterolibacterium are BmB in winter. In addition, BmB have good correlations with BmGs in the same season, which indicates that bacterial community changes drive different distributions of ARGs during seasonal changes and that LEfSe is an acute and effective method for finding significantly different ARGs and bacteria between two or more classes.In conclusion, this study demonstrated the seasonal changes of BmGs and BmB at two wastewater treatment systems.

https://www.sciencedirect.com/science/article/abs/pii/S0269749117333651