Yu Zhigang, Rabiee Hesamoddin, Guo Jianhua
Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
Water Res. 2021 Jun 15;198:117141. doi: 10.1016/j.watres.2021.117141. Epub 2021 Apr 10.
Antimicrobial resistance continues to be a rising global threat to public health. It is well recognized that wastewater treatment plants are reservoirs of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). However, traditional disinfection techniques are not effective to simultaneously remove ARB and ARGs, and the dynamic analysis of ARB inactivation have also been deficient. In this study, sulfidated nano zerovalent iron (S-nZVI) coupled with persulfate (PS) was applied to simultaneously remove both ARB (E. coli K-12 with RP4 plasmid) and ARGs (extra- and intracellular ARGs). S-nZVI/PS completely inactivated ARB (7.8-log reduction) within 10 min and degraded all extracellular ARGs (8.0-log reduction) within 5 min. These efficiencies were significantly higher (decay rate constant, k = 0.138 min) than those achieved individually (S-nZVI: k = 0.076 min; PS: k = 0.008 min), implying a synergistic effect between S-nZVI and PS against ARB and ARGs. The efficient removal rate of ARB was also supported by confocal microscopy and microfluidics at a single-cell level. The complete inactivation of ARB by S-nZVI/PS was also demonstrated in real drinking water and real wastewater effluent that contained natural organic matter and suspended solids. Regrowth assays showed that the treated ARB was not observed after 72 h or longer incubation, suggesting that ARB was permanently inactivated by radicals such as SO and •OH. The destruction of bacterial cells compromised the removal efficiency of the intracellular ARGs, with only ~4.0-log reduction after 60 min treatment by S-nZVI/PS. Collectively, our results suggest the feasibility of S-nZVI coupled with PS for simultaneous ARB and ARGs removal in real water matrices.
抗生素耐药性仍然是全球公共卫生领域日益严重的威胁。众所周知，污水处理厂是抗生素耐药菌（ARB）和抗生素耐药基因（ARG）的储存库。然而，传统消毒技术无法有效同时去除ARB和ARG，并且对ARB失活的动态分析也存在不足。在本研究中，硫化纳米零价铁（S-nZVI）与过硫酸盐（PS）联用，用于同时去除ARB（携带RP4质粒的大肠杆菌K-12）和ARG（细胞外和细胞内ARG）。S-nZVI/PS在10分钟内完全灭活ARB（7.8个对数级减少），并在5分钟内降解所有细胞外ARG（8.0个对数级减少）。这些效率显著高于单独使用时的效率（S-nZVI：k = 0.076分钟；PS：k = 0.008分钟），这意味着S-nZVI和PS对ARB和ARG具有协同作用。共聚焦显微镜和微流控技术在单细胞水平上也支持了ARB的高效去除率。S-nZVI/PS对ARB的完全灭活也在含有天然有机物和悬浮固体的实际饮用水和实际废水排放物中得到了证实。再生长试验表明，经过72小时或更长时间的培养后未观察到处理后的ARB生长，这表明ARB被SO和•OH等自由基永久灭活。细菌细胞的破坏降低了细胞内ARG的去除效率，S-nZVI/PS处理60分钟后，细胞内ARG仅减少约4.0个对数级。总体而言，我们的结果表明S-nZVI与PS联用在实际水基质中同时去除ARB和ARG的可行性。
