摘要
      抗生素和表面活性剂的过量使用导致它们在废活性污泥（WAS）中大量积累，但抗生素和表面表面活性剂对抗生素抗性基因（ARGs）命运的共同影响很少报道。本工作主要揭示了十二烷基苯磺酸钠（SDBS）在WAS厌氧发酵过程中对磺胺嘧啶（SDZ）胁迫ARGs分布的作用及其关键机制。高通量qPCR和宏基因组分析显示，SDBS加重了SDZ的选择压力，并加速了ARGs的增殖。ARGs的总丰度从SDZ中的8.81×1010增加到SDBS/SDZ共现系统中的1.17×1011拷贝/g TSS。具体而言，ermF（MLSB）、mefA（MLSB。SDBS有助于SDZ的溶解，同时有效分解细胞外聚合物物质和提高细胞膜通透性，这将促进SDZ的转运及其与ARGs宿主的相互作用。因此，微生物群落结构发生了明显变化，典型的ARGs宿主（即糖精和阿涅拉）得到了极大的富集。此外，与单独的SDZ相比，与ARGs繁殖相关的细胞信号转导系统（即glnL、glrK和pilG）、氧化应激反应（即frmA和recA）和细菌分泌系统（即VirB4）都在共发生的SDBS/SDZ反应器中被激发。PLS-PM分析表明，细菌群落是决定ARGs命运的主要因素，其次是可移动的遗传元件和代谢途径。这项工作证明了表面活性剂和抗生素对WAS发酵系统中ARGs命运的相互作用，并对不同外源污染物的生态风险产生了深刻的影响。
Abstract
The excessive application of antibiotics and surfactants resulted in their massive accumulation in waste activated sludge (WAS), but the co-occurrent impacts of antibiotics and surfactants on the antibiotic resistant genes (ARGs) fates have seldom reported. This work mainly revealed the roles and critical mechanisms of sodium dodecyl benzene sulfonate (SDBS) on the sulfadiazine (SDZ) stressing for ARGs distribution during WAS anaerobic fermentation. High-throughput qPCR and metagenomic analysis revealed that SDBS aggravated the SDZ selective pressure, and accelerated the proliferation of ARGs. The total abundance of ARGs was increased from 8.81 × 1010 in SDZ to 1.17 × 1011 copies/g TSS in the SDBS/SDZ co-occurrence system. Specifically, the absolute abundances of ermF (MLSB), mefA (MLSB), tetM-01 (tetracycline), tetX (tetracycline), sul2 (sulfonamide) and strB (aminoglycoside) were risen from 4.60 × 108–7.44 × 109 copies/g TSS in the SDZ reactor to 1.02 × 109–4.63 × 1010 copies/g TSS in SDBS/SDZ reactor. SDBS was contributed to the SDZ solubilization and simultaneously effective in disintegrating extracellular polymeric substances and improving cell membrane permeability, which would facilitate the SDZ transport and its interactions with ARGs hosts. Consequently, the microbial community structure was evidently altered, and the typical ARGs hosts (i.e., Saccharimonadales and Ahniella) were greatly enriched. Also, the cell signal transduction systems (i.e., glnL, glrK and pilG), oxidative stress response (i.e., frmA and recA) and bacterial secretion systems (i.e., VirB4), which were related with ARGs propagation, were all provoked in the co-occurred SDBS/SDZ reactor compared with that of sole SDZ. PLS-PM analysis suggested that the bacterial community was the predominant factor that determined the ARGs fates, followed by mobile genetic elements and metabolic pathway. This work demonstrated the interactive effects of surfactants and antibiotics on the ARGs fates in WAS fermentation systems and gave insightful implications on the ecological risks of different exogenous pollutants.

https://www.sciencedirect.com/science/article/abs/pii/S0048969723010562