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

抗生素是通过农业中用作肥料的污泥和粪便的扩散进入环境的。由于它们对细菌的有效作用，可能会影响土壤的重要功能，并可能干扰元素循环过程。研究了抗生素磺胺嘧啶对两个试验田几种氮循环基因表达的影响，以及对不同n转化过程的影响。效果是时间和剂量依赖的。然而，这项效果研究是在实验室条件下使用散装土壤进行的抗生素单次应用。特别是在现场条件下和重复施用后，没有关于磺胺嘧啶（和二氟沙星）或其他磺胺类药物（分别和氟喹诺酮类药物）对功能或结构多样性的影响的结果。为了评估抗生素在环境中的风险，实地实验是最重要的，因为抗生素在实地和实验室条件下的命运可能不同。土壤系统的异质性、植物群落的异质性、肥料的分布以及热点（如根际）土壤细菌的空间浓度决定了土壤效应的发生。此外，反复使用抗生素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.