School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China.
School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China.
Sci Total Environ. 2023 Jun 20;878:163142. doi: 10.1016/j.scitotenv.2023.163142. Epub 2023 Mar 28.
The occurrences and spread of antibiotic resistance (AR) mediated by horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs) in aquatic environment have been aggravated because of the abuse of antibiotics. While the pressure of different antibiotics is known to induce the spread of AR in bacteria, whether distribution of different antibiotics in cell structure could affect HGT risks is not clear. Here, a significant difference between the distribution of tetracycline hydrochloride (Tet) and sulfamethoxazole (Sul) in cell structure during electrochemical flow through reaction (EFTR) process was firstly reported. Meanwhile, EFTR treatment possessed excellent disinfection performance and consequently controlled the HGT risks. The intracellular Tet (iTet) was discharged through efflux pumps to increase the content of extracellular Tet (eTet) due to the resistance of donor E. coli DH5α under the selective pressure of Tet, declining the damage of donor and plasmid RP4. The HGT frequency was 8.18-fold increase compared with that by EFTR treatment alone. While the secretion of intracellular Sul (iSul) was inhibited by blocking the formation of efflux pumps to inactivate the donor under the Sul pressure, and the total content of iSul and adsorbed Sul (aSul) to be 1.36-fold higher than that of eSul. Therefore, the reactive oxygen species (ROS) generation and cell membrane permeability were improved to release ARGs, and •OH attacked plasmid RP4 in the EFTR process, inhibiting the HGT risks. This study advances the awareness of the interaction between distribution of different antibiotics in cell structure and the HGT risks in the EFTR process.
抗生素耐药性（AR）的发生和传播是由于抗生素的滥用，加剧了水平基因转移（HGT）介导的抗生素耐药基因（ARGs）在水生环境中的传播。虽然不同抗生素的压力被认为会诱导细菌中 AR 的传播，但不同抗生素在细胞结构中的分布是否会影响 HGT 风险尚不清楚。在这里，首次报道了在电化学流动反应（EFTR）过程中，盐酸四环素（Tet）和磺胺甲恶唑（Sul）在细胞结构中的分布存在显著差异。同时，EFTR 处理具有优异的消毒性能，因此控制了 HGT 风险。由于供体 E. coli DH5α对 Tet 的耐药性，在 Tet 的选择压力下，通过外排泵将细胞内的 Tet（iTet）排出，增加了细胞外的 Tet（eTet）的含量，从而降低了供体和质粒 RP4 的损伤。与单独进行 EFTR 处理相比，HGT 频率增加了 8.18 倍。而在 Sul 压力下，通过阻断外排泵的形成来抑制细胞内 Sul（iSul）的分泌，从而使失活供体，细胞内 Sul（iSul）和吸附 Sul（aSul）的总含量比细胞外 Sul（eSul）高 1.36 倍。因此，活性氧（ROS）的生成和细胞膜通透性提高，释放 ARGs，而•OH 在 EFTR 过程中攻击质粒 RP4，抑制 HGT 风险。本研究提高了对不同抗生素在细胞结构中的分布与 EFTR 过程中 HGT 风险之间相互作用的认识。
