Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Sci Total Environ. 2020 Jan 1;698:134236. doi: 10.1016/j.scitotenv.2019.134236. Epub 2019 Sep 2.
The widespread emergence of antibiotic resistance genes (ARGs) in drinking water systems endangers human health, and may be exacerbated by their horizontal gene transfer (HGT) among microbiota. In our previous study, Quorum sensing (QS) molecules produced by bacteria from biological activated carbon (BAC) biofilms were demonstrated to influence the transfer efficiency of a model conjugative plasmid, here RP4. In this study, we further explored the effect and mechanism of QS on conjugation transfer. The results revealed that Acyl-homoserine lactones producing (AHL-producing) bacteria isolated from BAC biofilm play a role in the propagation of ARGs. We selected several quorum sensing inhibitors (QSIs) to study their effects on AHL-producing bacteria, including the formation of biofilm and the regulating effect on conjugation transfer. In addition, the possible molecular mechanisms for AHLs that promote conjugative transfer were attributable to enhancing the mRNA expression, which involved altered expressions of conjugation-related genes. We also found that QSIs could inhibit conjugative transfer by downregulating the conjugation-relevant genes. We believe that this is the first insightful exploration of the mechanism by which AHLs will facilitate and QSIs will inhibit the conjugative transfer of ARGs. These results provide creative insight into ARG pollution control that involves blocking QS during BAC treatment in drinking water systems.
抗生素耐药基因（ARGs）在饮用水系统中的广泛出现危及人类健康，并且它们在微生物群之间的水平基因转移（HGT）可能会加剧这一问题。在我们之前的研究中，已经证明了来自生物活性炭（BAC）生物膜的细菌产生的群体感应（QS）分子会影响模型结合质粒 RP4 的转移效率。在本研究中，我们进一步探讨了 QS 对结合转移的影响和机制。结果表明，从 BAC 生物膜中分离出的产生酰基高丝氨酸内酯（AHL-producing）的细菌在 ARGs 的传播中起作用。我们选择了几种群体感应抑制剂（QSIs）来研究它们对 AHL 产生菌的影响，包括生物膜的形成和对结合转移的调节作用。此外，AHL 促进结合转移的可能分子机制归因于增强了涉及到与结合相关的基因的 mRNA 表达。我们还发现，QSIs 可以通过下调与结合相关的基因来抑制结合转移。我们相信，这是首次深入探讨 AHLs 促进和 QSIs 抑制 ARGs 结合转移的机制。这些结果为在饮用水系统中使用 BAC 处理时阻断 QS 以控制 ARG 污染提供了有创意的思路。
