This study evaluates the effects of a broad-spectrum antibiotic (florfenicol) on antibiotic resistance genes (ARGs) and bacterial community structure in aquatic environments. We constructed an indoor aquatic microcosm model, adding different concentrations of florfenicol (0.1, 1, 10, 100 mg L⁻¹), and water and sediment samples were collected after 0, 7, 30, and 60 days. qPCR and 16S rDNA amplicon sequencing were used to study the changes in the ARGs and bacterial community structure of the collected samples. The results show that the inclusion of florfenicol resulted in an increased abundance of the floR and optrA genes. Adding 100 mg L⁻¹ florfenicol to the water increased the abundance of optrA gene copies with the maximum on the Day 7, and increased the abundance of floR gene copies with the maximum on Day 30. Adding 100 mg L⁻¹ florfenicol to the sediment increased the abundance of floR and optrA genes by one order of magnitude on Day 60. Meanwhile, the average number of operational taxonomic units (OTUs) in the water samples was 257, and the average number of OTUs in sediment samples was 823. The bacterial community diversity and richness in sediments were higher than those in water. The difference between the maximal and minimal values of the Shannon diversity index in the water and sediment samples was 4.36 and 1.95, respectively. The effect of florfenicol on the bacterial community structure in water was much higher than that in sediment. At 30 days, the diversity index and richness index of the florfenicol treatment groups with 1 and 10 mg L⁻¹ concentrations began to increase; at 60 days, the diversity and richness indices of the 100 mg L⁻¹ florfenicol treatment group began to increase. The samples at the same sampling time in the sediments clustered closer together. The results of this study provide a scientific basis for guiding the rational use of florfenicol in aquaculture, maintaining a healthy and stable microecological environment in aquaculture, and provide theoretical data for environmental ecological risk assessment and safety management caused by microbial resistance under the abuse of florfenicol.

中文翻译：

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水生微观世界模型中广谱抗生素（氟苯尼考）对水和沉积物抗性基因和细菌群落结构的影响

本研究评估了广谱抗生素（氟苯尼考）对水生环境中抗生素抗性基因（ARGs）和细菌群落结构的影响。我们构建了一个室内水生微观世界模型，添加不同浓度的氟苯尼考（0.1、1、10、100 mg L ^-1），并在0、7、30和60天后收集水和沉积物样品。qPCR和16S rDNA扩增子测序用于研究采集样本的ARGs和细菌群落结构的变化。结果表明，氟苯尼考的​​加入导致floR和optrA基因的丰度增加。向水中添加 100 mg L ^-1氟苯尼考可增加 optrA的丰度基因拷贝数在第 7 天达到最大值，增加了floR基因拷贝的丰度，在第 30 天达到最大值。向沉积物中添加 100 mg L ^-1氟苯尼考增加了floR和optrA的丰度在第 60 天，基因数量减少了一个数量级。同时，水样中的操作分类单位（OTU）平均数为 257，沉积物样品中 OTU 的平均数为 823。高于水中的。水和沉积物样品中香农多样性指数的最大值和最小值之差分别为4.36和1.95。氟苯尼考对水中细菌群落结构的影响远高于沉积物中。^{30 d时，氟苯尼考1和10 mg·L -1}浓度处理组的多样性指数和丰富度指数开始增加；在 60 天，100 mg L ^{-1的多样性和丰富度指数}氟苯尼考治疗组开始增加。沉积物中同一采样时间的样品聚集得更近。本研究结果为指导水产养殖业合理使用氟苯尼考、维护健康稳定的水产养殖微生态环境提供科学依据，为氟苯尼考滥用下微生物耐药性引起的环境生态风险评估和安全管理提供理论数据。 .