Pollution Characteristics of Antibiotic Resistance Genes and Their Correlation with Environmental Factors in the Coastal Channel Catfish (Ictalurus punctatus) Aquaculture Areas of Jiangsu Province

Antibiotic resistance genes (ARGs) is a new type of pollutants. In order to understand the pollution level of ARGs and its influencing factors in the coastal channel catfish (Ictalurus punctatus) aquaculture areas of Jiangsu Province, a real-time fluorescent quantitative PCR technique was used in this study. The absolute abundance of 12 kinds of ARGs in the environment samples were detected and analyzed, and their correlation with environmental factors were investigated. Results show that: (1) The detection rates of sul1, sul2, tetA, tetM, tetQ, ermB, mphA and aad in water samples were 100%, and the detection rates of sul3, qnrB, qnrS and bla_CTX-M were between 50.0% and 83.3%. The total absolute abundance of ARGs in different sampling points was 3.83×10⁶-1.12×10⁷ copies·L^-1, among which sul1, tetA and tetM were the most abundant ARGs. (2) In sediment samples, the most noteworthy ARGs were Sulfonamides and Tetracyclines because of their detection rates (100%) and absolute abundances (up to 10⁷ orders of magnitude), and the detection rates of other ARGs were between 66.7% and 100%. (3) Characteristic ARGs in water and sediment samples vary in different regions. (4) Redundancy analysis combined with Pearson correlation analysis show that DO, ORP, EC, NO₃^--N, pH, WT and NH₄⁺-N were the key factors affecting the composition and distribution of ARGs in water, while in sediments were ORP, TOC, TN and TP. Overall, the composition of ARGs is abundant, among which sulfonamides and tetracyclines are the main detected ARGs, and the abundance of ARGs in sediment is higher than that in water. The distribution of ARGs show obvious regional characteristics. Environmental factors have a great influence on the composition, abundance and distribution of ARGs. This study offers basic data support for the risk assessment and prevention and control of ARGs in the coastal area of Jiangsu Province.