| 摘要: |
| 抗生素滥用及其引发的微生物耐药问题严重影响公众健康，也是国内外环境领域的研究热点。环境中抗生素的健康风险主要来自耐药菌及其携带的耐药基因（ARGs），而ARGs的水平转移是评估其健康风险的关键环节。整合子是诱发ARGs水平转移的重要遗传元件，也是导致多重耐药和产生超级细菌的关键元件，整合酶基因（intI）能捕获游离的ARGs并将其重组到基因盒中，帮助ARGs的水平转移并推动多重耐药细菌形成。采用基于DNA高通量测序的宏基因组学分析方法，比较了饮用水、生活污水、水产养殖废水和医疗废水4种典型水环境介质中intI的多样性、丰度差异性及其与ARGs的相关性，分析了intI的分布特征。结果表明，4种典型水环境中存在intI1、intI2、intI3、intI6和intI9共5种已明确分类的intI，总丰度为：生活污水>水产养殖废水>饮用水，且医疗废水>饮用水；多样性为：医疗废水>生活污水>水产养殖废水>饮用水；均匀度为：医疗废水>水产养殖废水、生活污水>饮用水；生活污水与水产养殖废水中整合酶基因的相似性较高，且饮用水、水产养殖废水和医疗废水中整合酶基因的相似性较高；5种intI中，intI1分布广、丰度高，且与5种抗生素耐药基因（磺胺类、大环内酯-林肯酰胺-链阳霉素、四环素类、氯霉素和甲氧苄氨嘧啶）的丰度具有显著相关性（r≥0.6，P<0.05）。 |
| 关键词: 水环境 整合酶基因 耐药基因 高通量测序 |
| DOI： |
| 分类号:X832 |
| 基金项目:国家自然科学基金资助项目（52192682）；南京大学卓越计划资助项目（ZYJH005） |
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| Distribution Characteristics of Integrase Genes in Typical Water Environment |
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LI Zi-han, ZHANG Xu-xiang, REN Hong-qiang
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State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China
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| Abstract: |
| The abuse of antibiotics, along with the problem of antibiotic resistance of microorganisms caused by them, makes a serious threat on human health and is also a hotspot in environmental field at home and abroad. The health risks of antibiotics in the environment mainly come from antibiotic resistant bacteria and their antibiotic resistant genes (ARGs), and the horizontal transfer of ARGs is a key step to evaluate their health risks. Integron is an important genetic element which induce horizontal transfer of ARGs, as well as a key element that leads to multiple antibiotic resistance and the generation of superbacteria. Meanwhile, integrase gene (intI) can encode tyrosine recombinases to catalyzes recombination of captured gene cassettes (GCs) containing different antibiotic resistance genes (ARGs), resulting in the horizontal transfer of ARGs and the multi drug resistance of bacteria. A metagenomic analysis method based on DNA high throughput sequencing was used to compare the diversity and abundance difference of integrons, as well as their correlationship with ARGs in drinking water, domestic wastewater, aquacultural wastewater and medical wastewater. The results showed that five well classified integrase genes, intI1, intI2,intI3,intI6, and intI9, were found in four typical water environments by metagenomic analysis and comparison with INTEGRALL database. The total abundance ranked as follows: domestic wastewater>aquaculture wastewater>drinking water, and medical wastewater>drinking water. The diversity arranged a sequence of medictal wastewater>domestic wastewater>aquaculture wastewater>drinking water. The degree of uniformity sequenced in the order of medical wastewater>domestic wastewater>drinking water, and medical wastewater>aquaculture wastewater>drinking water. There is a similarity between domestic wastewater and aquaculture wastewater on the gene composition and abundance of intI, as well as that of drinking water, aquaculture wastewater, and medical wastewater. Among the five integrase genes, intI1 was widely distributed and had high abundance, and there was a strong correlation between intI1 and the abundance of five antibiotic resistance genes including sulfonamide, tetracycline, chloramphenicol, macrolide lincosamide streptogramin (MLS), and trimethoprim ARGs (r≥ 0.6, P<0.05). |
| Key words: Water environment Integrase gene Antibiotic resistance genes High-throughput sequencing |
