Effects of veterinary medicines in manure on the abundance and transfer of bacterial antibiotic resistance genes in soils in dependence of varying soil moisture conditions

B3的研究表明，在两种不同的土壤中，重复处理的磺胺嘧啶（SDZ）的有机肥，抗性基因（sul 1，sul 2）的拷贝数显着增加相比，处理无除草剂的有机肥或对照，并积累重复应用。在田间条件下，SDZ抗性的可转移性显着增加，在地块处理的粪便来源于与SDZ药用猪。根际转移频率高于非根际土壤。含SDZ的粪肥对玉米和牧草根际土壤中sul基因丰度的影响在不同采样时间之间存在差异，这可能是由于气候因素造成的。我们假设，干燥和再湿润的原因转移的养分供应，植物渗出和生物可及的孔隙空间，这些变化影响SDZ的丰度和转移的抗性基因在土壤微生物群落的影响。为了阐明干燥-再湿润和温度的影响，并澄清这一缺失的环节，将调查从中央领域和实验室实验操纵的干燥和湿润循环的草的根际和根面的样品中的sul基因的丰度和它们的可转移性。在粪肥处理的土壤中的可转移的耐药基因组的焦磷酸测序将提供独特的见解质粒多样性和其他抗生素耐药基因的SDZ共同选择。

Research of B3 revealed that in two different soils repeatedly treated with sulfadiazine (SDZ)-containing manure, resistance gene (sul1, sul2) copies significantly increased compared to treatments with antibiotic-free manure or control, and accumulated with repeated applications. Under field conditions, the transferability of SDZ resistance was significantly increased in plots treated with manure originating from pigs medicated with SDZ. Transfer frequencies were higher in the rhizosphere compared to bulk soil. The effects of SDZ-containing manure on the abundance of sul genes in the rhizosphere of maize and grass varied between different sampling times supposedly due to climatic factors. We hypothesize that drying and re-wetting cause shifts of nutrient availability, plant exudation and bio accessible pore space, and that these shifts influence the effects of SDZ on abundance and transfer of resistance genes in soil microbial communities. In order to elucidate the effects of drying-rewetting and temperature and to clarify this missing link, the abundance of sul genes and their transferability will be investigated in samples taken from rhizosphere and rhizoplane of grass from the central field and laboratory experiments with manipulated drying and wetting cycles. Pyrosequencing of the transferable resistome in manure-treated soils will provide unique insights into plasmid diversity and other antibiotic resistance genes co-selected by SDZ.