发布者:抗性基因网 时间:2019-10-10 浏览量:873
摘要
最近越来越多的证据表明,重金属可以刺激细菌之间的抗生素抗性基因(ARG)的转移。但是,以前的大多数研究都集中在纯菌株上,尚未明确探索重金属对细菌群落(尤其是活性污泥)中ARG转移的影响。在这项研究中,结合计算机孵化器(Bioscreen C)和流式细胞仪的高通量方法被开发来评估不同浓度的重金属影响污泥细菌群落中ARG的转移。通过使用大肠杆菌MG1655作为宽宿主范围的IncP-1质粒pKJK5的供体,发现0.5 mmol / L Pb,0.1 mmol / L As和0.005 mmol / L Hg可以明显促进污泥细菌群落中的ARG转移。此外,在上述重金属胁迫下,微流控芯片上的交配测定还证明了在附着群落中的更高转移频率。分离并在系统发育上描述了在Pb,As和Hg胁迫下的转导结合体。对于砷和汞,优势属是假单胞菌,分别占88%和96%。在铅的胁迫下,气单胞菌属和肠杆菌属是主要的转导结合体,分别占56%和32%。此外,与重金属转运和细胞代谢有关的ABC转运蛋白和氨基酸代谢在预测转导结合剂的微生物代谢功能中占主导地位。这项研究可对污水处理厂中ARG传播的风险评估和控制提供帮助。
Recent growing evidence suggests that heavy metals can stimulate the transfer of antibiotic resistance genes (ARGs) between bacteria. However, most previous studies focused on pure strains, the effect of heavy metals on ARG transfer in bacterial communities, especially in activated sludge, has not been clearly explored. In this study, a high-throughput method, combining computerized incubator (Bioscreen C) and flow cytometry, was developed to evaluate different concentrations of heavy metals influencing ARG transfer in sludge bacteria communities. By using Escherichia coli MG1655 as the donor of broad-host range IncP-1 plasmid pKJK5, it was found that 0.5 mmol/L Pb, 0.1 mmol/L As and 0.005 mmol/L Hg could obviously promote ARG transfer in sludge bacteria communities. Furthermore, mating assays on microfluidic chips also proved higher transfer frequencies in attached communities under the above heavy metal stresses. Transconjugants under Pb, As and Hg stresses were isolated and phylogenetically described. For As and Hg, the dominant genus was Pseudomonas, accounting for 88% and 96%, respectively. While under Pb stress, the genera Aeromonas and Enterobacter were the main transconjugants, accounting for 56% and 32% respectively. Moreover, ABC transporters and Amino acid metabolism, which were related to heavy metal transport and cellular metabolism, were dominant in the prediction of microbial metabolic function of transconjugants. This study can be helpful for risk assessment and control of ARG spreading in WWTPs.
https://www.sciencedirect.com/science/article/pii/S0048969719338100