海南岛东海岸珊瑚礁生态系统中抗生素抗性基因的赋存特征

Occurrence and characteristics of antibiotic resistance genes in the coral reef ecosystems along the east coast of Hainan Island

为了解海南岛近岸珊瑚礁生态系统中抗生素抗性基因(Antibiotic Resistance Genes,ARGs)的赋存特征,本研究借助绝对定量PCR技术分析了海南岛东海岸8个珊瑚礁礁区海水中的磺胺类(sul1、sul2)、喹诺酮类(qnrB、qnrS)和氯霉素类ARGs(cmlA1-01、cmlA1-02、cmx(A))的丰度及其与海水盐度、营养盐(NH_(3)^(-)-N、NO_(2)^(-)-N、NO_(3)^(-)-N、PO_(4)^(3-)-P)和金属离子(Hg、As、Cu、Pb、Zn、Cd、Cr)浓度的相关性。结果发现,在8个调查站点海水中的磺胺类、喹诺酮类和氯霉素类共3类7种ARGs的检出率为100%,且sul2在所有调查站点中都是丰度最高的ARG(3.96×10^(7)~1.65×10^(9)copies·L^(−1))。此外,5种ARGs[sul1、qnrS、cmlA1-01、cmlA1-02、cmx(A)]的丰度与盐度显著负相关,而qnrS和cmlA1-01的丰度均与NO_(2)^(-)-N浓度显著正相关,sul1和qnrB的丰度分别与Cu和Cr浓度显著正相关。结果表明,海南岛东海岸珊瑚礁生态系统中存在多种类型的ARGs污染,盐度、营养盐和金属离子可能是驱动礁区ARGs传播的主要环境因素。

To understand the occurrence and characteristics of antibiotic resistance genes(ARGs)in the coastal coral reef ecosystem of Hainan Island,a survey was made in the seawater of the coral reef ecosystems along the east coast of Hainan Island,and the sea water at different depths was sampled at 8 survey sites to analyze its abundances of ARGs of sulfonamides(sul1 and sul2),quinolones(qnrB and qnrS),and chloramphenicol(cmlA1-01,cmlA1-02,and cmx(A)),and its correlation between ARGs abundances and environmental conditions including salinity,nutrient(NH_(3)^(-)-N,NO_(2)^(-)-N,NO_(3)^(-)-N,and PO_(4)^(3-)-P),and metal(Hg,As,Cu,Pb,Zn,Cd,and Cr)ion content by using real-time PCR-based absolute quantification.The results showed that the detection rates of 7 ARGs in the 3 types of sulfonamide,quinolone and chloramphenicol in the seawater at the 8 survey sites were 100%,and that sul2(3.96×10^(7)−1.65×10^(9)copies·L^(−1))was the most abundant in the seawater in all the coral reef ecosystems.Moreover,the absolute abundances of five ARGs(sul1,qnrS,cmlA1-01,cmlA1-02,and cmx(A))were negatively correlated with salinity.Meanwhile,the absolute abundances of both cmlA1-01 and qnrS were positively correlated with the NO_(2)^(-)-N content,and sul1 and qnrB were positively correlated with Cu and Cr,respectively.These results suggest that there should be many types of ARG pollutions in the coral reef ecosystems along the east coast of Hainan Island.Salinity,nutrients and metal ions may be the main environmental factors driving the spread of ARGs in the coral reef area.