State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China.
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
Environ Res. 2024 Dec 1;262(Pt 1):119780. doi: 10.1016/j.envres.2024.119780. Epub 2024 Aug 12.
Antimicrobial resistance (AMR) poses a global health threat to aquatic environments and its propagation is a hot topic. Therefore, deactivating antibiotic-resistant bacteria (ARB) and removing antibiotic resistance genes (ARGs) from water is crucial for controlling AMR transmission. Peracetic acid (PAA), which is known for its potent oxidizing properties and limited by-product formation, is emerging as a favorable disinfectant for water treatment. In this study, we aimed to assess the efficacy of pre-exposure to PAA followed by UV treatment (PAA-UV/PAA) compared with the simultaneous application of UV and PAA (UV/PAA). The focus was on deactivating vancomycin-resistant Enterococcus faecalis (VREfs), a typical ARB in water. Pre-exposure to PAA significantly enhanced the efficacy of subsequent UV/PAA treatment. At a UV fluence of 7.2 mJ cm, the PAA-UV/PAA method achieved a 6.21 log reduction in VREfs, surpassing the 1.29 log reduction observed with UV/PAA. Moreover, compared to UV/PAA, PAA-UV/PAA showed increased efficacy with longer pre-exposure times and higher PAA concentrations, maintaining superior performance across a broad pH range and in the presence of humic acid. Flow cytometry analysis indicated minimal cellular membrane damage using both methods. However, the assessments of superoxide dismutase (SOD) activity and adenosine triphosphate content revealed that PAA-UV/PAA induced greater oxidative stress under similar UV irradiation conditions, leading to slower bacterial regrowth. Specifically, SOD activity in PAA-UV/PAA surged to 3.06 times its baseline, exceeding the 1.73-fold increase under UV/PAA conditions. Additionally, pre-exposure to PAA amplified ARGs degradation and reduced resistance gene leakage, effectively mitigating the spread of AMR. Pre-exposure to 200 μM PAA for 10 and 20 min enhanced vanB gene removal efficiency by 0.14 log and 1.29 log, respectively. Our study provides a feasible approach for optimizing UV/PAA disinfection for efficient removal of ARB and ARGs.
抗微生物药物耐药性（AMR）对水生环境构成了全球性的健康威胁，其传播是一个热门话题。因此，从水中灭活抗生素耐药菌（ARB）和去除抗生素耐药基因（ARGs）对于控制 AMR 传播至关重要。过氧乙酸（PAA）具有强大的氧化特性和有限的副产物形成，作为一种有前途的水处理消毒剂正在出现。在这项研究中，我们旨在评估预暴露于过氧乙酸（PAA）然后进行紫外线处理（PAA-UV/PAA）与同时应用紫外线和 PAA（UV/PAA）相比的效果。重点是灭活水中的典型 ARB 万古霉素耐药粪肠球菌（VREfs）。预暴露于 PAA 可显著增强随后的 UV/PAA 处理的效果。在紫外线剂量为 7.2 mJ/cm 时，PAA-UV/PAA 方法使 VREfs 的减少量达到 6.21 log，超过了 UV/PAA 观察到的 1.29 log 的减少量。此外，与 UV/PAA 相比，PAA-UV/PAA 在更长的预暴露时间和更高的 PAA 浓度下显示出更高的功效，在广泛的 pH 范围内和存在腐殖酸的情况下保持卓越的性能。流式细胞术分析表明，两种方法均对细胞的细胞膜造成最小的损害。然而，超氧化物歧化酶（SOD）活性和三磷酸腺苷（ATP）含量的评估表明，在类似的紫外线照射条件下，PAA-UV/PAA 引起更大的氧化应激，导致细菌生长缓慢。具体而言，PAA-UV/PAA 中的 SOD 活性飙升至基线的 3.06 倍，超过了 UV/PAA 条件下的 1.73 倍增长。此外，PAA 的预暴露增强了 ARGs 的降解和降低了抗性基因的泄漏，有效抑制了 AMR 的传播。预暴露于 200 μM PAA 10 和 20 分钟分别将 vanB 基因去除效率提高了 0.14 log 和 1.29 log。我们的研究为优化 UV/PAA 消毒提供了一种可行的方法，以有效地去除 ARB 和 ARGs。
