摘要

       由于在废水处理过程中可能产生抗生素抗性细菌，废水中抗生素的存在已成为一个严重的问题。为了了解生物养分去除（BNR）过程中微生物群落和四环素抗性基因的动态变化，三个实验室规模的序批式反应器（SBR）在四环素胁迫下运行。结果表明，在分别存在 20 和 50μgL-1 的痕量四环素的情况下，微生物群落结构发生了改变，四环素外排泵基因在 150 天的运行中得到了增强。此外，当初始四环素浓度增加到 2 和 5mgL-1 时，观察到四环素抗性显着增强，伴随着微生物群落结构的急剧变化。在这项研究中，发现水平基因转移是在痕量四环素长期胁迫下四环素抗性基因发展的主要机制。在四环素抗性基因中观察到的变异中，大约 90.34% 可以用四环素抗性基因和 1 类整合子的潜在宿主的动力学来解释。需要注意的是，负责养分去除的功能菌（如硝化螺菌属、脱氯单胞菌属、红杆菌属和Candidatus_Accumulibacter）与四环素耐药性呈正相关，这可能会促进废水生物处理过程中四环素耐药性的流行。因此，本研究为 BNR 过程中四环素抗性基因及其微生物宿主的发生和流行提供了深入的见解。

       The occurrence of antibiotics in wastewater has become a serious concern due to the possible development of antibiotic resistant bacteria in wastewater treatment process. In order to understand the dynamics of microbial community and tetracycline resistance genes in biological nutrient removal (BNR) process, three lab-scale sequencing batch reactors (SBRs) were operated under the stress of tetracycline. Results indicated that microbial community structure was altered, and tetracycline efflux pump genes were enhanced over 150-day operation in the presence of trace tetracycline of 20 and 50 μg L−1, respectively. Furthermore, when the initial tetracycline concentrations were increased to 2 and 5 mg L−1, substantial enhancement of tetracycline resistance was observed, accompanied with a sharp shift in microbial community structure. In this study, horizontal gene transfer was found to be the main mechanism for the development of tetracycline resistance genes under the long-terms stress of trace tetracycline. About 90.34% of the observed variations in tetracycline resistance genes could be explained by the dynamics of potential hosts of tetracycline resistance genes and class 1 integron. It should be noticed that the functional bacteria (e.g. Nitrospira, Dechloromonas, Rhodobacter and Candidatus_Accumulibacter) responsible for nutrient removal were positively correlated with tetracycline resistance, which might promote the prevalence of tetracycline resistance during biological wastewater treatment. Consequently, this study provided in-depth insights into the occurrence and prevalence of tetracycline resistance genes and their microbial hosts in BNR process.

https://www.sciencedirect.com/science/article/pii/S030147971930283X