养殖水域抗生素抗性基因污染的研究概况与展望

Current status and prospect ofantibiotic resistance genes(ARGs) pollution in the aquaculture

在水产养殖中,抗生素是用来治疗细菌性疾病最有用的药物。但近些年的研究发现,过度使用抗生素,反而诱导产生了一系列带有抗性基因的致病菌,严重制约了水产养殖业的发展。本文以近15年来国内外相关研究的文献为依据,概括介绍了抗生素抗性基因(ARGs)的产生及其传播途径、ARGs污染的危害性、国内外ARGs污染研究现状及加强ARGs污染研究的必要性等4个方面的研究进展,围绕抗性基因的检测、ARGs的传播、扩散及作用机制和控制、消除ARGs的方法等方面进行了后续研究重点的展望,以期为我国水产养殖行业的可持续发展提供依据。

In aquaculture, aquatic products is often affected by bacterial diseases, which leads to the decline in production, while antibiotics are the most effective drug to treat the bacterial diseases. However, recent studies have found that the excessive use of antibiotics did not get to increase the expected economic output. On the contrary, it induced a series of pathogenic bacteria carrying the resistance genes, which seriously restricted the development of aquaculture. Currently, there are two sources for the antibiotic resistance genes （ARGs）. One is intrinsic resistance of bacteria in the environment which is the prototype of the resistance gene and quasi resistant gene existing in the bacterial genome or genes not expressed normally. The other is exogenous input which refers to the bacteria with resistance gene excreting through human or animal feces with the intestinal bacteria, and then entering the environment. The resistance gene can enhance the resistance of bacteria to antibiotics. So when the antibiotics enter the aquatic environment, the bacteria carrying the resistance gene will quickly multiply and become the dominant flora. In the water environment, because the genomes of aquatic bacteria are complex and diverse and they contain the genetic elements or genes that are capable of producing and spreading resistance genes. The resistance genes can transfer to the bacteria that do not contain resistance genes by horizontal gene transfer, and then through the food chain enrichment enter the human body eventnally. The majority of antibiotics in the environment will finally enter the water environment, therefore it is the most serious problem for the water environment and has become the most concerned environmental pollution. In some eastern coastal cities of China, aquaculture industry has become the pillar industry. And many breeding sites are located in the tidal flat, so the resistant strains and resistance genes is prone to diffusing into the Gulf and the waters of high seas. Once the resistance genes is transmitted to the aquatic organisms, it will cause irreversible damage to the whole aquatic ecosystem and even the neighboring countries can be polluted by the resistance genes, which will directly affect the our country＇ s image in the international import and export trade and the economic benefits. Existing studies have indicated that the presence of resistance genes led to the multiple drug resistance in bacteria. Aquatic ecosystem is the enriched library of the multiple antibiotic resistance genes, and the pollution of exogenous antibiotics to aquatic ecosystem is the important factor to induce ARGs＇ accumulation and dissemination. Researches about the pollution of the antibiotics and ARGs in the aquaculture environment stated relatively earlier abroad. A large number of antibiotics usage in aquaculture resulted in the emergence of drug resistance to the pathogens in fish, which led to the difficulies to be effective in the treatment of fish and even animals or human diseases. Though China is the largest country in aquaculture in the world, the relevant research still lagged behind. Thus, with the rapid development of China＇ s aquaculture industry and the continuous expansion of the scale of aquaculture, resistance gene not only led to the continuous decline in aquaculture production, but also had caused great .pressures on the environment. Moreover, with more and more attention paid on the food security, the possible problems brought by ARGs pollution in the aquaculture have been worried about in recent years. Therefore, it should systematically carry out antibiotics and ARGs pollution research in aquaculture environment, and establish methods for screening and identifying the resistant strains in aquaculture organisms and their environment, and analyze the environmental factors＇ （antibiotics, temperature, pH, dissolved oxygen, etc. ） influence on ARGs diffusion and the relevant mechanisms, and reveal the diffusion and propagation reguations of ARGs in aquaculture environment, and establish the method for the control and removal of antibiotics and ARGs in aquaculture environment. The paper summarized the research progress of the resistance gene pollution in cultured waters from four aspects, which were production and transmission of ARGs, the formation and harm of ARGs pollution, research status of ARGs pollution at home and abroad and the necessity of strengthening the study of ARGs pollution. The future research keynotes were also discussed at the end of this paper.