摘要

       抗生素抗性基因 (ARG) 在废水微生物群落中的传播越来越受到关注。膜生物反应器（MBR）在废水处理中的应用越来越广泛。我们假设细菌间 ARG 的转移可能发生在 MBR 中，MBR 结合了高密度的细菌细胞、生物膜和抗生素抗性细菌或 ARG。本研究通过计数板法、MIDI 微生物鉴定系统和定量聚合酶链反应 (qPCR) 技术研究了 MBR 中 RP4 质粒的转移规律和传播。结果表明，RP4 质粒从供体菌株到活性污泥中可培养细菌的平均转移频率为每个受体 2.76 × 10−5，高于先前报道的废水和细菌污泥中的转移频率。此外，活性污泥中的许多细菌物种通过水平转移获得了 RP4，而希瓦氏菌属、光杆菌属、假单胞菌属、变形杆菌属和弧菌属。更有可能获得这种质粒。有趣的是，总 DNA 中 RP4 质粒的丰度保持在高水平并且相对稳定在 104 拷贝/mg 生物固体，这表明在我们的研究中 ARG 从供体菌株转移到活性污泥细菌。因此，污水污泥中 ARG 的存在构成了潜在的健康威胁。

       Growing attention has been paid to the dissemination of antibiotic resistance genes (ARGs) in wastewater microbial communities. The application of membrane bioreactors (MBRs) in wastewater treatment is becoming increasingly widespread. We hypothesized that the transfer of ARGs among bacteria could occur in MBRs, which combine a high density of bacterial cells, biofilms, and antibiotic resistance bacteria or ARGs. In this study, the transfer discipline and dissemination of the RP4 plasmid in MBRs were investigated by the counting plate method, the MIDI microorganism identification system, and quantitative polymerase chain reaction (qPCR) techniques. The results showed that the average transfer frequency of the RP4 plasmid from the donor strain to cultivable bacteria in activated sludge was 2.76 × 10−5 per recipient, which was greater than the transfer frequency in wastewater and bacterial sludge reported previously. In addition, many bacterial species in the activated sludge had received RP4 by horizontal transfer, while the genera of Shewanella spp., Photobacterium spp., Pseudomonas spp., Proteus spp., and Vibrio spp. were more likely to acquire this plasmid. Interestingly, the abundance of the RP4 plasmid in total DNA remained at high levels and relatively stable at 104 copies/mg of biosolids, suggesting that ARGs were transferred from donor strains to activated sludge bacteria in our study. Thus, the presence of ARGs in sewage sludge poses a potential health threat.
https://www.sciencedirect.com/science/article/abs/pii/S016816561300343X