Selection for antibiotic resistance in complex microbial communities

越来越清楚的是，自然环境在抗生素耐药性的演变和传播中起着重要作用。本研究将确定受污染的自然环境（如污水处理厂下游）中细菌大量耐药基因的基因流的机制基础和意义。目前尚不清楚与污水处理厂相关的抗生素耐药生物的增加是由于耐药生物的不断排放，还是诸如多重耐药大肠杆菌等细菌在包括抗生素残留物在内的环境污染物的选择下，通过水平基因转移（HGT）在水生沉积物中持续存在和/或获得耐药基因。该项目将利用文化和文化独立方法进行的中观研究来研究复杂社区的抗性选择。后者将包括用于枚举关键标记基因的实时PCR和下一代测序（NGS），以确定单一抗生素、不同类别抗生素的混合物和污染废水的现场样本对所有已知抗性基因相对丰度的影响。这些知识将用于支持环境政策的制定和环境风险管理。

It is becoming increasingly clear that the natural environment plays an important role in the evolution and dissemination of antibiotic resistance. This studentship will determine the mechanistic basis and significance of gene flow that underlies the abundance of antimicrobial resistance genes in bacteria inhabiting polluted natural environments such as downstream of waste water treatment plants (WWTPs). It is unclear whether increased prevalence of antibiotic resistant organisms associated with WWTPs is due to constant emissions of resistant organisms or whether bacteria such as multi-drug resistant E. coli persist and/or acquire resistance genes by horizontal gene transfer (HGT) in aquatic sediments under selection by environmental pollutants including antibiotic residues. This project will study selection for resistance in complex communities utilising mesocosm studies interrogated using culture and culture independent methods. The latter will include real-time PCR for enumeration of key marker genes and next generation sequencing (NGS) to determine the effects of single antibiotics, mixtures of different classes of antibiotic and field samples of polluted effluents on relative abundance of all known resistance genes. This knowledge will be used to support environmental policy development and environmental risk management.