摘要

在废水生物处理过程中，抗生素耐药基因（ARGs）的普遍存在和积累是一个经常被检测到的问题，可能会给人类带来潜在的健康危机。本文研究了两种不同好氧颗粒污泥（AGS）培养过程中ARGs的命运。结果表明，传统AGS（T-AGS）培养法和强化AGS（E-AGS）培养法在ARGs迁移模式上有显著差异（P<0.005）。E-AGS过程中ARGs的平均相对丰度（0.280±0.079）高于T-AGS过程（0.130±0.041），而E-AGS过程中ARGs的富集强度（1.52～5.29倍）低于T-AGS过程（3.79～75.31倍）。TnpA和intI1作为携带ARGs的两种不同类型的可移动基因元件，分别在T-AGS（r=0.902，P<0.050）和E-AGS（r=0.823，P<0.001）过程中对基因水平转移有显著贡献。与T-AGS进程（17个宿主）相比，E-AGS进程中出现了更高的HGT水平，并检测到更多可能存在ARGs的宿主（25个宿主）。同时，过大的AGS可能会增加几种抗生素失活ARGs的传播，因此不建议使用。总体而言，无论在T-AGS过程还是E-AGS过程，当它被用在半工业规模的程序式反应器中来处理城市污水，ARG的积累和扩散是不可避免的。所以应重视对种子污泥进行适当的预处理，同时对AGS中的ARGs进行深度去除处理，使ARGs相对丰度保持在较低水平。

The prevalence and accumulation of antibiotic resistance genes (ARGs) were frequently detected in biological wastewater treatment processes, which might cause potential health crisis to human. In present study, the fates of ARGs during two different aerobic granular sludge (AGS) cultivation processes were investigated. The results showed that traditional AGS (T-AGS) cultivation process and enhanced AGS (E-AGS) cultivation process had significant differences (P < 0.005) in ARGs shift patterns. E-AGS process had higher average relative abundance (0.280 ± 0.079) of ARGs than T-AGS process (0.130 ± 0.041), while the intensity of ARGs enrichment during E-AGS (1.52–5.29 fold) was lower than T-AGS (3.79–75.31 fold) process. TnpA and intI1 as two different types of mobile genetic elements (MGEs) carrying ARGs, were observed to contribute significantly to the horizontal gene transfer (HGT) during T-AGS (r = 0.902, P < 0.050) and E-AGS (r = 0.823, P < 0.001) processes, respectively. Higher HGT level took place and more possible potential hosts (25 hosts) harboring ARGs were detected during E-AGS process comparing with T-AGS process (17 hosts). Meanwhile, over large AGS might increase the propagation of several antibiotic deactivation ARGs, so it was not advised. Overall, whether during T-AGS or during E-AGS process which was applied in a pilot-scale sequencing batch reactor treating municipal wastewater, the accumulation and spread of ARGs were inevitable. It should be valued that some suitable pre-treatments of seed sludge should be executed, meanwhile, advanced treatment for removing of ARGs in AGS should be conducted to maintain the relative abundances of ARGs at relatively low level.

https://www.sciencedirect.com/science/article/pii/S0160412019342047