| 历史抗生素胁迫改变磺胺甲唑和甲氧苄啶对活性污泥的影响:ARGs及其潜在宿主 |
| 摘要点击 1440 全文点击 913 投稿时间：2022-01-15 修订日期：2022-02-21 |
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| 中文关键词 抗生素 复合污染 遗留效应 全尺度分类 抗生素抗性基因(ARGs) 网络分析 |
| 英文关键词 antibiotic compound pollution legacy effects full-scale classification antibiotic resistance genes (ARGs) network analysis |
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| 中文摘要 |
| 抗生素共暴露对污水处理厂抗生素抗性基因（ARGs）及微生物群落聚集过程有着重要影响.然而，历史抗生素接触胁迫差异（遗留效应）是否能决定微生物和ARGs对抗生素复合污染的响应尚不清楚.通过选择高浓度（30 mg ·L-1）磺胺甲唑（SMX）和甲氧苄啶（TMP）作为历史接触胁迫条件，探究SMX和TMP复合污染对ARGs、细菌群落及其交互作用的短期影响.基于高通量荧光定量PCR，共检测出13种ARGs，它们的绝对丰度介于2.21~5.42 copies ·μL-1（对数值，以DNA计，下同），其中sul2、ermB、mefA和tetM-01是样品中最主要的亚型，绝对丰度在2.95~5.40 copies ·μL-1之间；SMX和TMP复合污染会引起ARGs和可移动基因元件（MGEs）的富集，但其对各亚型的影响不同，且SMX的历史遗留效应高于TMP；不同接触史的复合污染下，ARGs间的共现与互斥模式均存在；MGEs （尤其是intI-1）与磺胺类（sul1、sul2）、四环素类［tet （32）］和大环内酯-林可酰胺-链霉菌素类抗性基因（ermB）均呈显著正相关性；基于微生物全尺度分类发现各类群微生物群落结构对复合污染的响应不同，且条件丰富菌属（CAT）得到了显著富集；陶厄氏菌属（Thauera）、假黄单胞菌属（Pseudoxanthomonas）和副球菌属（Paracoccus）是优势的抗性菌属；网络分析共发现31个ARGs的潜在宿主，以条件稀有菌属（CRT）为主，尤其是Candidatus_Alysiosphaera和纺锤状菌属（Fusibacter）与多种ARGs呈现正相关，是多种ARGs的潜在公共细菌宿主；部分稀有菌属［RT，变异杆菌属（Variibacter）、气单胞菌属（Aeromonas）和管道杆菌属（Cloacibacterium）等］是转座子IS 613的潜在宿主，在ARGs的增殖传播中发挥重要作用.综上，研究揭示了污水处理系统中抗生素历史胁迫对ARGs赋存特征和及其宿主细胞的遗留效应，可为削减抗生素复合污染引起的ARGs污染提供新思路与理论依据. |
| 英文摘要 |
| The co-exposure of antibiotics has important effects on antibiotic resistance genes (ARGs) and microbial community aggregation in wastewater treatment plants (WWTPs). However, it is unclear whether differences in historical antibiotic exposure stress can determine responses of microbes and ARGs to combined antibiotics. By selecting a high concentration (30 mg·L-1) of sulfamethoxazole (SMX) and trimethoprim (TMP) as historical exposure stress conditions, the effects of SMX and TMP-combined pollution on ARGs, bacterial communities, and their interactions were explored in short-term experiments. Based on high-throughput quantitative PCR, a total of 13 ARGs were detected, and the absolute abundance was 2.21-5.42 copies·μL-1 (logarithm, DNA, the same below). Among them, sul2, ermB, mefA, and tetM-01 were the main subtypes in the samples, and the absolute abundance was between 2.95 and 5.40 copies·μL-1. The combined contamination of SMX and TMP could cause the enrichment of ARGs and mobile genetic elements (MGEs); however, their effects on each subtype were different, and the historical legacy effect of SMX was higher than that of TMP. Under the different exposure histories, the co-occurrence and co-exclusion patterns existed between ARGs. Moreover, MGEs (especially intI-1) were significantly correlated with sulfonamides (sul1 and sul2), tetracyclines[tet(32)], and macrolide-lincosamide-streptogramin (MLSB) resistance genes (ermB). Based on the full-scale classification of microorganisms, it was found that the microbial community structure of various groups responded differently to combined pollution, and the conditionally abundant taxa (CAT) were obviously enriched. Thauera, Pseudoxanthomonas, and Paracoccus were the dominant resistant bacterial genera. Furthermore, a total of 31 potential hosts of ARGs were identified with network analysis, which were dominated with conditionally rare taxa (CRT). Particularly, Candidatus_Alysiosphaera and Fusibacter were positively correlated with most of the ARGs, being the common protentional hosts. Importantly, some rare genera (RT, Variibacter, Aeromonas, Cloacibacterium, etc.) were potential hosts of transposon IS613, which played an important role in the proliferation and spread of ARGs. In conclusion, this study revealed the legacy effects of historical antibiotic stress on ARGs and their hosts, which could provide new ideas and theoretical basis for reducing ARGs pollution in WWTPs. |
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