This study mainly investigated the environmental risks of polyhexamethylene guanidine (PHMG) occurred in waste activated sludge (WAS) on the antibiotic resistance genes (ARGs) spread during anaerobic fermentation, and disclosed the critical mechanisms. The total ARGs abundance was increased by 32.2–46.4% at different stressing levels of PHMG. The main resistance mechanism categories of ARGs shifted to the target alternation and efflux pump. PHMG disintegrated WAS structure and increased the cell permeability, which benefitted the mobile genetic elements (MGEs) release and horizontal transfer of ARGs. Besides, PHMG induced the enrichment of potential ARGs hosts (i.e., Burkholderia, Bradyrhizobium and Aeromonas). Moreover, PHMG upregulated the metabolic pathways (i.e., two-component system, quorum sensing, and ATP-binding cassette transporters) and critical genes expression (i.e., metN, metQ, rpfF, rstA and rstB) related with ARGs generation and dissemination. Structural equation model analysis revealed that microbial community structure was the predominant contributor to the ARGs propagation.

本研究主要考察了废弃活性污泥（WAS）中聚六亚甲基胍（PHMG）对厌氧发酵过程中抗生素抗性基因（ARGs）传播的环境风险，并揭示了其中的关键机制。在不同的 PHMG 胁迫水平下，总 ARGs 丰度增加了 32.2-46.4%。ARGs的主要阻力机制类别转移到目标交替和外排泵。PHMG分解WAS结构并增加细胞通透性，有利于移动遗传元件（MGEs）的释放和ARGs的水平转移。此外，PHMG 诱导了潜在的 ARGs 宿主（即伯克霍尔德氏菌、慢生根瘤菌和气单胞菌）的富集。）。此外，PHMG 上调了与 ARGs 产生和传播相关的代谢途径（即双组分系统、群体感应和 ATP 结合盒转运蛋白）和关键基因表达（即 metN、metQ、rpfF、rstA和rstB）。结构方程模型分析表明，微生物群落结构是 ARGs 传播的主要贡献者。