摘要
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尽管三级污水处理工艺对化学污染物的去除效率很高，但在降低微生物风险方面还没有明确的结论。本研究利用宏基因组方法揭示了抗生素耐药性基因（ARGs）、毒力因子基因（VFGs）的变化、它们的共存以及多个TWTP过程中潜在宿主的变化。结果表明，TWTP降低了废水中的化学污染物，但反硝化生物过滤器（DB）显著增加了所选抗生素抗性细菌和ARGs的绝对丰度，同时通过富集多药耐药性基因和攻击性基因提高了ARGs和VFGs的相对丰度。此外，ARGs和VFG（如bacA–tapW、mexF–adeG）的共存仅在DB处理后才被发现，且均由假单胞菌携带。然后，紫外线和人工湿地处理通过减轻抗生素耐药性和致病性，在降低微生物风险方面表现出良好的互补性。网络和装箱分析表明，隶属于假单胞菌和不动杆菌的关键操作分类单元的转移可能有助于TWTP期间ARGs和VFGs的动态变化。总的来说，这项研究为TWTP如何影响抗生素耐药性和VFG谱以及应选择哪些TWTP来减轻微生物风险提供了新的线索。
Abstract
Abstract Image
Despite the high removal efficiency for chemical pollutants by tertiary wastewater treatment processes (TWTPs), there is no definite conclusion in terms of microbial risk mitigation yet. This study utilized metagenomic approaches to reveal the alterations of antibiotic resistance genes (ARGs), virulence factor genes (VFGs), their co-occurrence, and potential hosts during multiple TWTPs. Results showed that the TWTPs reduced chemical pollutants in wastewater, but the denitrifying biofilter (DB) significantly increased the absolute abundances of selected antibiotic-resistant bacteria and ARGs, and simultaneously elevated the relative abundances of ARGs and VFGs through the enrichment of multidrug resistance and offensive genes, respectively. Moreover, the co-occurrence of ARGs and VFGs (e.g., bacA–tapW, mexF–adeG) was only identified after the DB treatment and all carried by Pseudomonas. Then, the ultraviolet and constructed wetland treatment showed good complementarity for microbial risk reduction through mitigating antibiotic resistance and pathogenicity. Network and binning analyses showed that the shift of key operational taxonomic units affiliating to Pseudomonas and Acinetobacter may contribute to the dynamic changes of ARGs and VFGs during the TWTPs. Overall, this study sheds new light on how the TWTPs affect the antibiotic resistome and VFG profiles and what TWTPs should be selected for microbial risk mitigation.

https://pubs.acs.org/doi/abs/10.1021/acs.est.2c06168