摘要

    在生物废水处理过程中经常检测到抗生素抗性基因（ARG）的流行和积累，这可能对人类造成潜在的健康危机。在本研究中，研究了两种不同的好氧颗粒污泥（AGS）培养过程中ARGs的命运。结果表明，传统的AGS（T-AGS）栽培工艺和增强型AGS（E-AGS）栽培工艺在ARGs转换模式上有显着差异（P <0.005）。 E-AGS过程的ARGs平均相对丰度（0.280±0.079）比T-AGS过程（0.130±0.041）高，而E-AGS期间ARGs富集的强度（1.52-5.29倍）低于T-AGS（ 3.79–75.31倍）过程。 TnpA和intI1作为携带ARG的两种不同类型的移动遗传元件（MGE），在T-AGS（r = 0.902，P <0.050）和E-AGS（r =分别为0.823，P <0.001）。与T-AGS过程（17个主机）相比，在E-AGS过程中检测到了更高的HGT水平，并且检测到更多可能的潜在宿主（25个主机）带有ARG。同时，过大的AGS可能会增加几种抗生素失活ARG的传播，因此不建议使用。总体而言，无论是在T-AGS还是在处理城市污水的中试规模分批反应器中应用的E-AGS过程中，ARG的积累和扩散都是不可避免的。应该重视对种子污泥进行一些适当的预处理，同时，应进行高级处理以去除AGS中的ARG，以将ARGs的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