我国沿海典型水产养殖水域底泥中抗生素抗性细菌的多样性分析

Diversity of abundant antibiotic-resistant bacteria in sediments from typical mariculture sites of China's coastline

在水产养殖中,大量使用抗生素会改变水域中的菌落结构,并会诱导产生抗生素抗性菌,对养殖生物及人类健康构成潜在威胁。为初步掌握当前我国沿海养殖密集水域抗性菌的多样性概况,对我国沿海11个典型养殖区的底泥进行采样,选用常见的6种抗生素对菌株进行筛选,并基于Illumina MiSeq测序平台对抗性菌进行多样性分析。结果显示:1)不同养殖水域,其底泥中抗性菌的多样性存在一定的差异; 2)在大部分养殖水域,抗性菌属于变形菌门和厚壁菌门; 3)养殖水域底泥中细菌的多样性在不同抗生素的作用下差异显著。研究结果表明,海水养殖中使用抗生素对抗性菌多样性影响显著。研究结果有助于全面了解水产养殖活动对我国沿海典型养殖区抗性细菌多样性的影响,并可为抗生素使用的生态风险评估和应对策略提供参考。

In the process of aquaculture,the heavy use of antibiotics will change the bacterial structure in aquaculture waters,and will induce a large number of bacteria carrying antibiotic resistance genes,which is becoming a threat to the health of aquatic animals and human beings.In order to understand the biodiversity of antibiotic-resistant bacteria in the main intensive mariculture areas along the coastaline of China,this study selected 11 typical coastal aquaculture sites and sampled the substrate sludge.Two kinds of tetracyclines(tetracycline,oxytetracycline hydrochloride),two kinds of quinolones(ciprofloxacin,enrofloxacin),and two kinds of sulfonamides(sulfadiazine,sulfamethoxazole)were chosen to screen and characterize bacteria,respectively.IlluminaMiSeq high throughput sequencing platform was used to analyze the diversity of antibiotic-resistant bacteria.The results showed that:(1)There is a significant difference in the diversity of antibiotic-resistant strains between different mariculture sites.The Chao index shows that the richness of anti-sulfamethoxazole bacterial communities is the highest and the richness of anti-enrofloxacin and ciprofloxacin bacterial communities are lower in most mariculture areas.In general,the richness of bacterial communities in the northern mariculture area is higher than that in the southern mariculture area.The Shannon index shows that in most mariculture areas,the diversity of bacterial communities in the sediment of antibiotics resistant to tetracycline and sulfonamide antibiotics are higher than the diversity of bacterial communities in the sediment of antibiotics resistant to quinolones,particularly among the highest diversity of bacterial communities resistant to sulfadiazine.(2)In most aquaculture waters,antibiotic-resistant bacteria belong to Gammaproteobacteria and Firmicutes.In most of the waters,there are major advantages of Gammaproteobacteria,followed by the Firmicutes,and the advantage of Gammaproteobacteria in the mariculture area in the south is greater than that in the North Sea.In the sediments of most of the marine culture area,there are major advantages of Firmicutes,followed by the Gammaproteobacteria.(3)The diversity of bacteria in aquaculture waters is significantly different under selective pressure of different antibiotics.The results showed that antibiotics used in mariculture significantly affected the diversity of antibiotic-resistant bacteria.The marine aquaculture has little effect on the bacteria in intensive aquaculture area on the level of phylum classification.But at the level of genus classification,the addition of different antibiotics can significantly change the diversity and richness of bacterial communities through the cluster analysis of each sample;with the addition of the same kind of antibiotics,the similarity of bacterial communities in adjacent waters is not high and there are great differences in the composition and structure of the bacterial community in the sediments from the northern and southern waters.The results could provide a basic data for understanding the effects of antibiotics on bacterial colonies in typical mariculture areas in the coastal waters of China,and provide reference information for ecological risk assessment and coping strategies of use of antibiotics.