低浓度抗生素胁迫下城市给水管网管壁生物膜特性及微生物多样性研究

Urban water supply network is an important part of the water supply system. The microbes in the water supply network can attach to the tube wall to form the biomembrane which will fall off the water with aging and cause the microorganisms in the water pipe to exceed the standard. In recent years, Resistant bacteria and resistance genes detected in water in urban water supply networks in recent years have posed a potential threat to human health. By means of molecular biology, this project will identify the resistant bacteria in the biomembrane on the water supply pipe wall, reveal the effect of antibiotics on the formation of resistant bacteria in biomembrane of water supply pipe wall, study the diversity and community succession of bacteria in the biofilm of water pipe wall under the action of antibiotics, and analyse the role of antibiotics in the formation of biofilm in the wall. Based on the genetic study of the resistance gene transfer in the biofilm of the wall under the action of antibiotics, the formation process of the resistant bacteria and resistance genes in the biofilm of the water supply wall will be revealed, and water biological safety assessment method for water supply network in the presence of resistance gene will be established. Also, the project will explore the regulation mechanism of the biofilm of the urban water supply network under the low concentration of antibiotic stress and the regulation mechanism of the resistant bacteria population. It can provide scientific basis and technical support for the control of biofilm of water supply wall, and the basis for improving the water quality of drinking water in water supply network.

城市给水管网的管壁生物膜会对造成水中微生物超标，而城市给水管网水中检出的抗性细菌和抗性基因对人类健康造成了潜在威胁。本项目通过分子生物学手段，对给水管壁生物膜中抗性细菌进行鉴定，揭示抗生素对给水管壁生物膜中抗性细菌形成的影响，研究抗生素胁迫下给水管壁生物膜中菌种群多样性和群落演替规律，解析抗生素在管壁生物膜形成中的作用。通过对抗生素作用下管壁生物膜中抗性基因的转移的基因学研究，揭示给水管壁生物膜中抗性菌和抗性基因的形成和转移过程，并建立抗性基因存在下的给水管网水生物安全性评价方法，探索基于低浓度抗生素胁迫下城市给水管网管壁生物膜调控方法和抗性菌种群的调控机制，为给水管壁生物膜的控制和提高给水管网水质提供科学依据和技术支持。

给水管网水中存在的痕量抗生素及其降解产物会促进抗性菌、抗性基因等新型污染物的产生，威胁饮水安全。除了抗生素抗性外，部分细菌对消毒剂也存在抗性。给水管网中大量微生物以附着在给水管壁上的生物膜形式存在，研究抗生素存在下管壁生物膜对消毒剂的抗性及抗生素存在下生物膜的生物多样性对于保证饮用水安全具有重要意义。研究选取四环素、磺胺嘧啶及其降解产物脱水四环素、脱水差向四环素、2-氨基嘧啶和对氨基苯磺酸为研究对象，研究不同抗生素及其降解产物与氯共同作用下对给水管网水质、管壁生物膜形成特性及耐氯性的影响，并从抗性基因和生物多样性的角度分析耐氯性机制。研究发现，抗生素及其降解产物单独或与氯联合作用时对pH、浊度、溶解氧和电导率等常规水质参数基本没有影响。水中微量抗生素及其降解产物能促进悬浮态微生物生长，其浓度越低对悬浮菌的促进作用越显著，在抗生素及其降解产物原水中添加0.3mg/L氯能有效抑制悬浮态微生物和生物膜生物增长。在一定范围内，抗生素及其降解产物作用浓度越大，生物膜耐氯性越强。当水中同时存在抗生素及其降解产物和0.3mg/L的氯时，管壁生物膜耐氯性较未加氯时增加。氯浓度在1mg/L以内时，提高其浓度对改善生物膜耐氯性没有明显影响。抗生素及其降解产物作用下生物膜生物多样性降低，生物膜抗性基因相对丰度增加，其中以磺胺嘧啶及其降解产物作用下sul2、sul3抗性基因和四环素及其降解产物作用下TETPB抗性基因相对丰度增加最为明显。此外还发现生物膜胞外聚合物含量增加，多糖增加明显。氯和抗生素及其降解产物共同作用下生物膜生物多样性较未加氯时降低，生物膜中新增了生丝微菌属、Roseateles、红细菌属、分枝杆菌属、Nordella、寡养食单胞菌属等优势菌。生物膜部分抗性基因相对丰度的促进作用较未加氯时更明显。