摘要
      抗生素抗性细菌（ARB）的应激反应和抗生素抗性基因（ARGs）的传播对水生环境和人类构成了严重威胁。本研究主要探讨了非均相光催化氧化（UVA-TiO2系统）对ARB应激反应机制的影响，不同的抗生素抗性作用靶点包括细胞壁、蛋白质、DNA、RNA、叶酸和细胞膜。结果表明，四环素和磺胺甲恶唑耐药大肠杆菌DH5α以蛋白质和叶酸的合成为靶点，其应激反应机制可以通过相关抗生素耐药性作用靶基因的过表达快速诱导全局调节因子。不同的应激反应系统是通过交叉保护机制介导的，与其他ARB相比，对不良环境的耐受性更强。此外，细菌细胞的光催化失活机制和细胞应激机制的分级反应导致了抗生素耐药性作用靶标的应激机制强度的差异。与分别靶向DNA和RNA合成的对萘啶酸和利福平具有耐药性的大肠杆菌DH5α相比，分别靶向细胞壁和细胞膜合成的对头孢噻肟和多粘菌素具有耐药性的DH5α对细菌存活和更高的偶联转移频率具有更大的优势。这一新观点提供了关于光催化氧化在灭活ARB和阻碍ARG在水生环境中传播方面的实际应用的详细信息。
Abstract
The stress response of antibiotic-resistant bacteria (ARB) and the spread of antibiotic resistance genes (ARGs) pose a serious threat to the aquatic environment and human beings. This study mainly explored the effect of the heterogeneous photocatalytic oxidation (UVA-TiO2 system) on the stress response mechanism of ARB with different antibiotic resistance action targets, including the cell wall, proteins, DNA, RNA, folate and the cell membrane. Results indicate that the stress response mechanism of tetracycline- and sulfamethoxazole-resistant E. coli DH5α, which targets the synthesis of protein and folate, could rapidly induce global regulators by the overexpression of relative antibiotic resistance action target genes. Different stress response systems were mediated via cross-protection mechanism, causing stronger tolerance to an adverse environment than other ARB. Moreover, the photocatalytic inactivation mechanism of bacterial cells and a graded response of cellular stress mechanism caused differences in the intensity of the stress mechanism of antibiotic resistance action targets. E. coli DH5α resistant to cefotaxime and polymyxin, targeting synthesis of the cell wall and cell membrane, respectively, could confer greater advantages to bacterial survival and higher conjugative transfer frequency than E. coli DH5α resistant to nalidixic acid and rifampicin, which target the synthesis of DNA and RNA, respectively. This new perspective provides detailed information on the practical application of photocatalytic oxidation for inactivating ARB and hampering the spreading of ARGs in the aquatic environment.

https://www.sciencedirect.com/science/article/abs/pii/S0043135422003633