摘要

       厌氧生物技术可以有效去除抗生素抗性细菌（ARB）和抗生素抗性基因（ARGs），但需要更好地了解其机制。在这里，我们采用生物电化学系统 (BES) 作为平台来研究天然四环素和磺胺耐药大肠杆菌菌株及其 ARG 的命运。从生活废水中分离出携带 intI1、sulI 和 tet(E) 的大肠杆菌菌株，并将其加入管状 BES。 BES 首先作为微生物燃料电池 (MFC) 运行，在阴极进行曝气，当从高电流切换到开路时，可将大肠杆菌和 ARGs 的去除率提高约 2 log（即数量级）操作模式。然后将 BES 作为微生物电解池 (MEC) 运行以排除氧扩散的影响，并且在开路配置期间去除大肠杆菌和 ARGs 再次比在高电流模式下高 1-2 log。大肠杆菌与电流 (R2 = 0.73) 和 ARG 与大肠杆菌的显着相关性（R2 范围为 0.54 至 0.87），并且 BES 底物不含电子受体这一事实暗示大肠杆菌的持久性。大肠杆菌及其 ARG 由 BES 中固有电子受体的可用性决定，即阳极电极或由外电原产生的电子穿梭。随后用纯培养的四环素和耐磺胺类大肠杆菌在两室 MEC 和血清瓶中孵育的实验表明，大肠杆菌可以通过呼吸阳极电极和/或外生电释放的电子穿梭而存活，并且 ARGs 持续存在他们的宿主大肠杆菌。

       Anaerobic biotechnologies can effectively remove antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), but there is a need to better understand the mechanisms. Here we employ bioelectrochemical systems (BES) as a platform to investigate the fate of a native tetracycline and sulfonamide-resistant Escherichia coli strain and its ARGs. The E. coli strain carrying intI1, sulI and tet(E) was isolated from domestic wastewater and dosed into a tubular BES. The BES was first operated as a microbial fuel cell (MFC), with aeration in the cathode, which resulted in enhanced removal of E. coli and ARGs by ~ 2 log (i.e., order of magnitude) when switched from high current to open circuit operation mode. The BES was then operated as a microbial electrolysis cell (MEC) to exclude the effects of oxygen diffusion, and the removal of E. coli and ARGs during the open circuit configuration was again 1–2 log higher than that at high current mode. Significant correlations of E. coli vs. current (R2 = 0.73) and ARGs vs. E. coli (R2 ranged from 0.54 to 0.87), and the fact that the BES substrate contained no electron acceptors, implied that the persistence of the E. coli and its ARGs was determined by the availability of indigenous electron acceptors in the BES, i.e., the anode electrode or the electron shuttles generated by the exoelectrogens. Subsequent experiments with pure-culture tetracycline and sulfonamide-resistant E. coli being incubated in a two-chamber MEC and serum bottles demonstrated that the E. coli could survive by respiring anode electrode and/or electron shuttles released by exoelectrogens, and ARGs persisted with their host E. coli.

https://www.sciencedirect.com/science/article/abs/pii/S0048969716314450