摘要

    抗生素耐药性已被公认为对全球公共健康的主要威胁。抗生素抗性细菌（ARB）的灭活和抗生素抗性基因（ARGs）的降解对于防止抗生素抗性在环境中的传播至关重要。常规的消毒方法可以有效灭活水传播的病原体，但不能完全消除抗生素耐药性风险。这项研究探索了光芬顿过程灭活ARB并降解细胞外和细胞内ARG（分别为e-ARG和i-ARG）的潜力。使用带有两个质粒编码的ARG（tetA和blaTEM-1）的大肠埃希氏菌DH5α作为ARB模型，在可见LED和中性pH条件下应用光芬顿30分钟内，去除了6.17 log ARB。此外，在48小时后未发生ARB再生，表明该过程对诱导ARB永久消毒非常有效。在各种水基质（包括超纯水（UPW），模拟废水（SWW）和磷酸盐缓冲液（PBS））下对光芬顿法进行了验证。与其他基质相比，在SWW中观察到更高的灭活效率。基于短和长扩增子的实时定量PCR，光Fenton过程还导致eARGs减少6.75至8.56 log。原子力显微镜（AFM）进一步证实，细胞外DNA被剪切成短DNA片段，从而消除了传播抗生素抗性的风险。与e-ARGs相比，需要更高剂量的Fenton试剂来破坏i-ARGs。另外，与blaTEM-1基因相比，tetA基因更容易降解。总的来说，我们的结果表明光芬顿法是一种有前途的技术，可以对水进行消毒以防止抗生素耐药性的扩散。

    Antibiotic resistance has been recognized as a major threat to public health worldwide. Inactivation of antibiotic resistant bacteria (ARB) and degradation of antibiotic resistance genes (ARGs) are critical to prevent the spread of antibiotic resistance in the environment. Conventional disinfection processes are effective to inactivate water-borne pathogens, yet they are unable to completely eliminate the antibiotic resistance risk. This study explored the potential of the photo-Fenton process to inactivate ARB, and to degrade both extracellular and intracellular ARGs (e-ARGs and i-ARGs, respectively). Using Escherichia coli DH5α with two plasmid-encoded ARGs (tetA and blaTEM-1) as a model ARB, a 6.17 log ARB removal was achieved within 30 min of applying photo-Fenton under visible LED and neutral pH conditions. In addition, no ARB regrowth occurred after 48-h, demonstrating that this process is very effective to induce permanent disinfection on ARB. The photo-Fenton process was validated under various water matrices, including ultrapure water (UPW), simulated wastewater (SWW) and phosphate buffer (PBS). The higher inactivation efficiency was observed in SWW as compared to other matrices. The photo-Fenton process also caused a 6.75 to 8.56-log reduction in eARGs based on quantitative real-time PCR of both short- and long amplicons. Atomic force microscopy (AFM) further confirmed that the extracellular DNA was sheared into short DNA fragments, thus eliminating the risk of the transmission of antibiotic resistance. As compared with e-ARGs, a higher dosage of Fenton reagent was required to damage i-ARGs. In addition, the tetA gene was more easily degraded than the blaTEM-1 gene. Collectively, our results demonstrate the photo-Fenton process is a promising technology for disinfecting water to prevent the spread of antibiotic resistance.

    https://www.sciencedirect.com/science/article/abs/pii/S0043135420304152