Characteristics of antibiotic resistance genes and microbial communities in marine sediments in seas of China

Abstract Marine sediments have been regarded as hotspots of antibiotic resistance genes (ARGs) due to the continuous release of antibiotics and ARGs into seas. A comprehensive study on the spatial distribution of ARGs in sediments from different seas is needed for a better understanding of ARGs pollution in China. Marine sediments were collected from the Bohai Sea, the Yellow Sea, the East China Sea, and the South China Sea, and five prevalent ARGs (i.e., blaTEM, sul1, tetA, tetC, and vanA) and one class 1 integron-integrase gene (intI1) were targeted and determined. β-lactam resistance genes blaTEM were ubiquitous and predominant in all sea areas with higher relative abundances up to 2.7×10− 3, followed by sulfonamide (sul1) and tetracycline resistance genes (tetC). IntI1 genes were detected in all sediments except for one sampling site in the South China Sea, with relative abundances ranging from 3.6 × 10− 5 to 1.3 × 10− 3. Total ARGs were more abundant in the South China Sea, followed by the Yellow Sea, the East China Sea, and the Bohai Sea. Microbial community analysis showed that the microbial community in sediments collected from different seas were clustered separately and appeared distinct spatial characteristics. Contents of nitrate, organic carbon, and total carbon are the major physicochemical properties that influence the distribution and variation of blaTEM and tetC in sediments with their p-value lower than 0.05. Co-occurrence network analysis revealed that Bacteroidetes and Firmicutes were dominant potential host bacteria of blaTEM, tetC, sul1, and int1. This study provides new insight into the pollution status of ARGs in the seas of China, which contributes to the ARGs risk assessment and raises awareness of managing antibiotic resistance pollution.