Effects of veterinary medicines on the functional diversity of the microbial biomass in soils

抗生素通过在农业中用作肥料的污泥和粪肥的扩散进入环境。由于它们对细菌的有效性，重要的土壤功能可能会受到影响，元素循环过程可能会受到干扰。研究了磺胺嘧啶对两种供试土壤中几个氮循环基因表达的影响以及对不同氮转化过程的影响。作用呈时间和剂量依赖性。然而，该效应研究是在实验室条件下使用散装土壤单次施用抗生素进行的。特别是在田间条件下和重复施用后，没有关于磺胺嘧啶（和双氯噻嗪）或其他磺胺类药物（和氟喹诺酮类药物）对功能或结构多样性影响的结果。为了评估抗生素在环境中的风险，田间实验是最重要的，因为抗生素的命运可能在田间和实验室条件下不同。土壤系统的异质性、植物群落、粪肥的分布和热点（如根际）土壤细菌的空间集中程度决定了土壤中的影响。此外，抗生素的重复应用可能会改变微生物群落的反应模式。

Antibiotics enter the environment by dispersion of sludge and manure used as fertilizer in agriculture. Due to their effectiveness against bacteria important soil functions could be affected and processes in element cycles might be disturbed. Studying the antibiotic sulfadiazine changes in the gene expressions of several N-cycling genes as well as effects on different N-transformation processes of two test soils were detected. The effects were time and dose dependent. However this effect study was performed with a single application of the antibiotic under laboratory conditions and using bulk soil. Especially no results on effects on functional or structural diversity of sulfadiazine (and difloxazin) or other sulfonamides (and fluroquinolones, respectively) are available under field conditions and after repeated application. To asses the risks of antibiotics in the environment field experiments are most important since the fate of antibiotics might differ under field and laboratory conditions. The heterogeneity of the soil system, plant communities, the manure distribution and the spatial concentration of soil bacteria in hot spots, like the rhizosphere, determine the occurrence of effects in soils. Furthermore repeated application of the antibiotics might change the response pattern of microbial communities.