东寨港红树林沉积物与水体中抗生素抗性基因的组成特征分析

Composition characteristics of antibiotic resistance genes in sediments and water in Dongzhaigang mangrove

【目的】通过探索海南东寨港红树林抗生素抗性基因(ARGs)的分布情况及微生物和ARGs之间的关联特征,了解红树林的抗性污染现状,为环境中抗性基因风险评估提供理论支撑。【方法】采用宏基因组学技术,探索海南东寨港红树林沉积物与水体中抗生素抗性基因的组成、多样性以及与微生物的相互关系。【结果】利福平抗性基因rpoB mutants、达托霉素类药物抗性基因rpoC、氟喹诺酮类药物抗性基因mfd、氨基香豆素抗性基因alaS、乙酰氧基耐药基因EF-Tu mutants、大环内酯类抗性基因macB以及异烟肼耐药基因katG是海南东寨港红树林水域的优势基因。沉积物和水体中抗生素抗性基因种类组成相似,但水体中抗性基因的多样性皆高于沉积物。NMDS分析发现,沉积物与水体ARGs的组成、分布明显不同。ARGs与微生物类群的关联分析表明,α-变形菌纲、γ-变形菌纲、β-变形菌纲以及黄杆菌纲是与ARGs关联较强的主要微生物类群,占比高达70%。水体中抗性基因主要来源于α-变形菌纲、β-变形菌纲和黄杆菌纲,而沉积物中抗性基因主要来源于γ-变形菌纲和δ-变形菌纲。【结论】红树林沉积物和水体中具有不同的ARGs组成特征,沉积物与水体具有不同的抗性基因风险特征,因此对红树林耐药微生物和ARGs进行生态监测和治理时,除重点监测微生物的组成特征外,还应关注水体中ARGs的变化规律,从而预测海南东寨港红树林沉积物微生物的耐药性风险。

【Objective】The study explored the distribution of antibiotic resistance genes(ARGs)in mangroves and the association between microorganisms and ARGs in order to understand the current situation of mangrove resistance pollution and provide theoretical support for risk assessment of ARGs in the environment.【Method】Metagenomics technique was used to explore the composition,diversity and relationship with microorganisms of antibiotic resistance genes in mangrove sediments and water in Dongzhaigang,Hainan province.【Result】The rifampicin resistance gene rpoB mutants,daptomycin resistance gene rpoC,fluoroquinolone resistance gene mfd,aminocoumarin resistance gene alaS,acetoxy resistance gene EF-Tu mutants,macrolide resistance gene macB and isoniazid resistance gene katG were dominant genes in this area.The composition types of antibiotic resistance gene in sediment and water were similar,but the diversities of antibiotic resistance gene in water were higher than those in sediment.However,NMDS analysis showed that the composition and distribution of ARGs in sediments and water bodies were obviously different.The correlation analysis between ARGs and microbial groups showed thatα-Proteobacteria,γ-Proteobacteria,β-Proteobacteria and Flavobacteriia were the main microbial groups strongly associated with ARGs,accounting for 70%.Among them,the resistance genes in water were mainly distributed inα-Proteobacteria,β-Proteobacteria and Flavobacteriia,while the resistance genes in sediments were mainly distributed inγ-Proteobacteria andδ-Proteobacteria.【Conclusion】Mangrove sediments and water bodies have different composition characteristics of ARGs,and they both have different risk characteristics.As a result,when carrying out ecological monitoring and management of drug-resistant microorganisms and ARGs in mangroves,attention should be paid not only to monitoring the compositional characteristics of microorganisms,but also to the pattern of change of ARGs in the water body,in order to predict the risk of drugresistance of microorganisms in sediment in this area of mangroves in Dongzhaigang,Hainan.