摘要

    通过定量PCR确定了次氯酸盐（NaClO和Ca（ClO）2）在废物活性污泥（WAS）发酵过程中减少抗生素抗性基因（ARGs）的有效性。 NaClO和Ca（ClO）2对ARG的命运表现出明显的影响。 Ca（ClO）2可以有效去除所有研究的ARGs，并且效率高度依赖于剂量。出乎意料的是，NaClO处理以较低的效率减弱ARG，甚至导致某些ARG（即aadA1和tetQ）以较高的剂量传播。细胞外聚合物的溶解和膜完整性表明，不稳定的NaClO最初会对细菌产生急性影响，而由于迅速消耗氧化ClO-，无法进一步减弱从宿主释放的ARGs。如果没有持久的强氧化应激，耐受性ARGs宿主的微生物活性将部分恢复，然后有助于ARGs在整个属中的传播。相反，固态Ca（ClO）2缓慢释放，并通过破坏细胞膜并去除从宿主释放的敏感ARGs，对细菌表现出延长的作用。此外，细菌类群-ARG网络分析表明，Ca（ClO）2减少了潜在宿主的数量，而Ca（ClO）2显着下调了与ARGs繁殖有关的代谢途径和基因表达，这有助于有效地抑制ARGs的繁殖。

    The effectiveness of hypochlorites (NaClO and Ca(ClO)2) on the reduction of antibiotic resistance genes (ARGs) during waste activated sludge (WAS) fermentation was determined by the quantitative PCR. NaClO and Ca(ClO)2 exhibited distinct effects on ARGs fates. Ca(ClO)2 was effective in removing all investigated ARGs, and the efficiency was highly dose-dependent. Unexpectedly, the NaClO treatment attenuated ARGs with lower efficiency and even caused the propagation of certain ARGs (i.e., aadA1 and tetQ) at higher doses. The extracellular polymeric substances dissolution and membrane integrity suggested that unstable NaClO had acute effects on bacteria initially, while it was ineffective to further attenuate ARGs released from hosts due to the rapid consumption of oxidative ClO-. Without lasting and strong oxidative stress, the microbial activities of tolerant ARGs hosts will partially recover and then contribute to the ARGs dissemination across genera. In contrast, solid-state Ca(ClO)2 was slowly released and exhibited prolonged effects on bacteria by disrupting cell membranes and removing the susceptible ARGs released from hosts. Furthermore, bacterial taxa-ARG network analysis indicated that Ca(ClO)2 reduced the abundance of potential hosts, and the metabolic pathway and gene expression related to ARGs propagation were significantly downregulated by Ca(ClO)2, which contributed to efficient ARGs attenuation.

    https://www.sciencedirect.com/science/article/abs/pii/S0304389420320008