Exploring a cradle of multi-resistant bacteria -- antibiotic resistance in soil and its link to different land use types and intensities

对多种抗生素具有耐药性的人类致病菌对公众健康构成威胁，被认为是21世纪全球面临的主要挑战之一。这些细菌携带的一些抗生素抗性基因可以追溯到土壤来源，并可能通过地下水或野生动物等传播。在这个项目中，土壤抗生素耐药性库的动态将沿着三个生物多样性探索区内广泛的土地利用类型和强度进行分析。为了更好地评估土地利用对抗生素抗性基因丰度的影响，我们将对所有草地EP和森林VIP样地的土壤DNA进行实时定量pcr分析。在一个微观实验中，包括细菌群落动态的评估和量化，解读了土地利用引起的抗生素耐药土壤细菌群落概况的变化。另一个重点是确定随不同土地利用类型和强度而发生的质粒发生的变化，因为这些移动的遗传因素是抗生素耐药性的主要来源并有助于其传播。在这种情况下，我们将确定IncP-1质粒的丰度，它可以携带多种抗生素抗性决定因素，并允许基因在远亲细菌之间转移。抗生素耐药基因包藏的环状质粒的总体多样性将通过应用长读测序方法来估计。此外，将对先前构建的土壤宏基因组文库进行基于功能的筛选，以发现抗生素抗性基因丰富度的差异以及与土地利用强度相关的机制。为了预测人类活动对多重耐药细菌传播的可能后果，迫切需要全面了解不同土地利用类型和强度对土壤抗生素耐药性的影响。该项目将提供有关土地利用对土壤抗生素耐药性库和转移潜力影响的详细信息。此外，在生物多样性探索研究平台内的密切合作将阐明土壤中抗生素耐药性与非生物以及生物因素（如重金属浓度或真菌分类群的丰度）之间的联系。

Human pathogenic bacteria resistant to multiple classes of antibiotics pose risks to public health and are considered as one of the major global challenges within the 21st century. Some of the antibiotic resistance genes carried by these bacteria have been traced to soil origins and can potentially spread via e.g., groundwater or wildlife. In this project, the dynamics of soil`s antibiotic resistance pool will be analyzed along a wide array of land use types and intensities within the three Biodiversity Exploratories. To provide robust assessment of land use impacts on antibiotic resistance gene abundance levels, real-time quantitative PCR-based analysis of soil DNA derived from all grassland EP and forest VIP plots will be carried out. Land use-induced changes in community profiles of antibiotic-resistant soil bacteria are deciphered within a microcosm experiment, including assessment and quantification of bacterial community dynamics. Another focus is the identification of shifts in plasmid occurrence accompanying different land use types and intensities, as these mobile genetic elements are a major source for antibiotic resistance and contribute to its dissemination. In this context, we will determine the abundance of IncP-1 plasmids, which can carry multiple antibiotic resistance determinants and allow gene transfer between distantly related bacteria. Overall diversity of antibiotic resistance gene-harboring circular plasmids will be estimated by applying a long-read sequencing approach. Moreover, function-based screening of previously constructed soil metagenomic libraries will be performed, to discover differences in richness of antibiotic resistance genes and mechanisms associated with land use intensity. To predict possible consequences of anthropogenic activities on spread of multi-resistant bacteria, comprehensive knowledge on antibiotic resistance in soil affected by different land use types and intensities is urgently required. This project will provide detailed information about land use impacts on soil`s antibiotic resistance reservoir and transfer potential. Furthermore, close collaborations within the Biodiversity Exploratories research platform will elucidate linkages between antibiotic resistance in soil and abiotic as well as biotic factors such as heavy metal concentrations or abundance of fungal taxa.