摘要

       选择压力，例如化学或重金属污染，可能共同选择环境中的细菌抗生素抗性。然而，水处理中的氯化是否可以共同选择抗生素抗性细菌是有争议的。在这项研究中，高容量定量聚合酶链反应 (qPCR) 分析被应用于在城市废水二次流出物中检测到的细菌中几乎所有已知的抗生素抗性基因 (ARG)（282 种类型）和 13 种移动遗传元件 (MGE)。氯化后的处理厂。结果表明，在非氯化样品中检测到 125 种独特的 ARG，随着氯浓度的增加，数量减少（79-91 种）。此外，在 4 mg Cl2/l 的情况下，ARG 的水减少了 7.49 × 104–3.92 × 107 拷贝/100 ml。考虑到 ARG 的相对丰度（即 ARG 拷贝标准化为 16S rRNA 基因拷贝），119 个 ARG 响应氯化而减少，而只有 6 个 ARG，如 dfrA1、tetPB-03、tetPA、ampC-04、tetA-02、和 erm(36)，分别可能富集 10.90、10.06、8.63、6.86、3.77 和 1.09 倍。此外，氯化后 12 种检测到的 MGE 的相对丰度较低。因此，氯化有效地减少了 ARG 和 MGE，而不是共同选择它们。

       Selective pressures, such as chemical or heavy metal pollution, may co-select for bacterial antibiotic resistance in the environment. However, whether chlorination in water treatment can co-select antibiotic-resistant bacteria is controversial. In this study, high capacity quantitative polymerase chain reaction (qPCR) analysis was applied to target almost all known antibiotic-resistance genes (ARGs) (282 types) and 13 mobile genetic elements (MGEs) in bacteria detected in secondary effluents from a municipal wastewater treatment plant after chlorination. The results revealed that 125 unique ARGs were detected in non-chlorinated samples, and the number decreased (79–91 types) as the chlorine concentration was increased. Moreover, 7.49 × 104–3.92 × 107 copies/100 ml water reduction of ARGs occurred with 4 mg Cl2/l. Considering the relative abundance of ARGs (i.e., ARG copies normalized to 16S rRNA gene copies), 119 ARGs decreased in response to chlorination, whereas only six ARGs, such as dfrA1, tetPB-03, tetPA, ampC-04, tetA-02, and erm(36), were potentially enriched by 10.90-, 10.06-, 8.63-, 6.86-, 3.77-, and 1.09-fold, respectively. Furthermore, the relative abundance of 12 detected MGEs was lower after chlorination. Therefore, chlorination was effective in reducing ARGs and MGEs rather than co-selecting them.

https://www.sciencedirect.com/science/article/abs/pii/S0045653516306415