Fluoroquinolone antibiotics (FQs) are one of the most widely used antibiotics, which are new pollutants with 'pseudo persistence' in the environment, causing great ecological risks. FQs could change the structure and function of microbial communities and affect nitrogen cycling mediated by microorganisms. Consequently, FQs would change the composition of various types of nitrogen in the environment and exert a significant impact on the global nitrogen cycling. We encapsulated the distribution of FQs in the environment and its impacts on nitrogen cycling mediated by microorganisms, explained the role of FQs in each key process of nitrogen cycling, aiming to provide an important reference for revealing the ecological effects of FQs. Generally, FQs could be detected in various environmental media, with significant differences in the concentration and types of FQs in different environments. Ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin are the four types of FQs with the highest detection frequency and concentration. The effect of FQs on nitrogen cycling deeply depends on typical characteristics of concentration and species. FQs mainly inhibit nitrification by reducing the abundance of amoA gene related to ammoxidation process and the abundance and composition of ammoxidation bacteria. FQs inhibits nitrification by reducing the abundance and composition of microbial communities. The denitrification process is mainly inhibited due to the reduction of the activity of related enzymes and the abundance of genes such as narG, nirS, norB, and nosZ genes, as well as the abundance and composition of denitrifying functional microorganisms. The process of anammox is restricted due to the reduction of the abundance, composition and hzo gene abundance of anaerobic anammox bacteria. FQs lead to the reduction of active nitrogen removal and the increase of N2O release in the environment, with further environmental problems such as water eutrophication and greenhouse effect. In the future, we should pay attention to the effects of low concentration FQs and complex antibiotics on the nitrogen cycling, and focus on the effects of FQs on the changes of nitrogen cycle-related microbial monomers and communities.
氟喹诺酮类抗生素(FQs)是使用量最大的抗生素之一,是一种在环境中具有“伪持久性”的新型污染物,具有巨大的生态风险。FQs会改变微生物群落结构和功能从而影响微生物介导的氮循环过程,改变环境中各种类型氮的组分,进而对全球氮循环产生重要影响。本文总结了FQs污染现状及对微生物介导氮循环的影响,以阐明FQs对氮循环各个关键过程的作用,从而为揭示FQs的生态效应研究提供科学依据。FQs普遍存在于各类环境介质中,不同环境中FQs浓度和种类存在显著差异,其中氧氟沙星、诺氟沙星、环丙沙星和恩诺沙星是检出频率和浓度最高的4种FQs。FQs对氮循环的作用过程具有典型的剂量和种类依赖型特征。FQs主要通过降低氨氧化过程相关的amoA基因丰度和氨氧化细菌丰度、组成来抑制硝化过程;主要通过降低相关酶活性和narG、nirS、norB和nosZ等基因丰度,以及降低反硝化功能属微生物丰度、组成来抑制反硝化过程;通过降低厌氧氨氧化细菌丰度、组成和hzo基因丰度来限制厌氧氨氧化过程;最终导致环境中活性氮去除的降低和氧化亚氮(N2O)释放的增加,甚至进一步诱发水体富营养化和温室效应等环境问题。未来应重点关注低浓度FQs和复合抗生素对氮循环过程的影响,进一步加强FQs对氮循环微生物单体和群落变化影响的研究。.
Keywords: fluoroquinolones antibiotics (FQs); functional gene.; inhibition; microorganism; nitrogen cycle.