Factors influencing the removal of antibiotic-resistant bacteria and antibiotic resistance genes by the electrokinetic treatment
Factors influencing the removal of antibiotic-resistant bacteria and antibiotic resistance genes by the electrokinetic treatment
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DOI：
10.1016/j.ecoenv.2018.05.028
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发表时间：
2018-09-30
影响因子：
6.8
通讯作者：
Zhu, Changxiong
中科院分区：
文献类型：
--
作者：
Li, Hongna;Li, Binxu;Zhu, Changxiong
在不同影响因素下，研究了电动修复工艺对水体中耐药菌和耐药基因的去除效果。以金霉素（CTC）、土霉素（OTC）和四环素（TC）为模板剂，随着电压梯度的增大（0.4-1.2 V cm（-1））和反应时间的延长（3-14 d），ARB和ARGs的去除率均提高。施加1.2 V cm（-1）的电压时，去除率最高（ARB为26.01-31.48%，ARG为37.93-83.10%），导致最高的耗电量。极性反转间隔时间对ARB灭活率的影响顺序为0 h（66.06-80.00%）> 12 h（17.07-24.75%）> 24 h（10.44-13.93%）。与24 h的极性反转间隔相比，12 h的极性反转间隔可使土壤中的pH值降低，电流密度增大，电压降分布更加均匀，从而使土壤中的电化学反应更加有效。与sul基因相比，泰特基因更容易受到电场的攻击。这主要是由于泰特基因（tetM除外）丰度较低以及电动修复过程对不同ARG的影响不同。此外，主要由于外排泵上调的机制，获得了相对较小的tetC和tetG去除率。泰特和sul基因均与TC耐药菌呈正相关。外排泵基因tetG和细胞保护基因tetM与ARB的相关性不同。本研究加深了对ARB和ARGs去除策略的理解，并为电动处理去除ARB和ARGs提供了重要参数。
The performance of the electrokinetic remediation process on the removal of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) was evaluated with different influencing factors. With chlortetracycline (CTC), oxytetracycline (OTC), and tetracycline (TC) as template chemicals, the removal of both ARB and ARGs was enhanced with the increase of voltage gradient (0.4-1.2 V cm(-1)) and prolonged reaction time (3-14 d). The greatest removal (26.01-31.48% for ARB, 37.93-83.10% for ARGs) was obtained applying a voltage of 1.2 V cm(-1), leading to the highest electrical consumption. The effect of polarity reversal intervals on the inactivation ratio of ARB followed the order of 0 h (66.06-80.00%) > 12 h (17.07-24.75%) > 24 h (10.44-13.93%). Lower pH, higher current density, and more evenly-distributed voltage drop was observed with a polarity reversal interval of 12 h compared with that of 24 h, leading to more efficient electrochemical reactions in soil. Compared with sul genes, tet genes were more vulnerable to be attacked in an electric field. It was mainly attributed to the lower abundance of tet genes (except tetM) and the varied effects of electrokinetic remediation process on different ARGs. Moreover, a relatively less removal ratio of tetC and tetG was obtained mainly due to the mechanism of the efflux pump upregulation. Both tet and sul genes were positively correlated with TC-resistant bacteria. The efflux pump genes like tetG and the cellular protection genes like tetM showed different correlations with ARB. This study enhances the current understanding on the removal strategies of ARB and ARGs, and it provides important parameters for their destruction by the electrokinetic treatment.