洪泽湖沉积物中四环素土霉素及相关抗性基因的分布特征及潜在风险分析

The distribution characteristics and potential risk of tetracycline, oxytetracycline and their corresponding genes pollution in sediment of Hongze Lake

为了探讨洪泽湖沉积物中四环素、土霉素及其抗性基因的含量、分布及潜在风险,采集洪泽湖湖区42个沉积物样品,利用HPLC-MS测定了样本中常见的两种四环素类抗生素(四环素、土霉素)含量,并采用q PCR分析了样品中3种四环素抗性基因(tet A、tet C、tet M)的含量。结果显示,四环素类抗生素检出率为100%,含量范围为1.35~25.43μg·kg^(-1)。所有样品中tet A、tet C基因均有检出,且tet C基因含量最高,平均含量为9.77×106copies·g-1,只在部分样品中检测出tet M。相关结果分析表明,沉积物中的四环素类抗性基因含量与四环素类抗生素含量及有机碳的乘积呈较为明显的正相关关系(R2=0.669 4,n=42),这也表明在洪泽湖水域中,四环素类抗生素抗性基因的含量水平可能不仅与环境中的抗生素暴露水平相关,同时也有可能与有机质含量等环境因素相关。

Antibiotic resistance genes（ARGs）have been a great concern to the environmental health in the world. This study was focus on the content, distribution and potential risk of tetracycline, oxytetracycline and the corresponding resistance genes in the sediments from the Hongze Lake, to find out the relationship between the selected antibiotics and its induced resistance genes. The sediment samples was collected in forty two spots all over the lake for the subsequent analysis. The high-performance liquid chromatography-mass spectrograph（HPLC-MS）was used to investigate the concentration of two common tetracycline antibiotics（tetracycline, oxytetracycline）, moreover,quantitative real-time PCR was used to study the abundance of three typical tetracycline resistance genes in the samples. The results showed that the two tetracycline（TCs）antibiotics are detected in all samples, with the contents of tetracycline antibiotics ranging from 1.35 μg·kg（-1）to 25.43 μg·kg（-1）. The tet A and tet C genes were detected in all samples, in contrast, the tet M gene was partially found in some samples. Among the three genes, tet C gene was in a higher level than other two genes. Furthermore, the relevance analysis indicated that the abundance of tetracycline resistance genes in the sediment of Hongze Lake, were not only related to content of tetracycline antibiotics, but also to the other environmental factors as organic carbon. This result showed that the appearance of ARGs in the environment is a comprehensive process, and the elimination of ARGs should be based on the well treatment on the antibiotics as well as other ambient factors.