Characteristics and driving factors of antibiotic resistance genes in aquaculture products from freshwater ponds in China Yangtze River Delta

ABSTRACTAntibiotic resistance genes (ARGs) are widespread in aquaculture and pose a huge threat to aquaculture organisms and human health. In this study, occurrences and relative abundances of ARGs were analysed in the guts of products cultured in freshwater ponds in the Yangtze River Delta region in China. A total of 29 ARGs were found in the gut samples, with detection frequencies ranging from 4.8% to 81%, and the relative abundances (ARGs/16S rRNA) ranging from 10−7 to 1. In addition, the human dietary intake of ARGs via aquaculture products was assessed, where the daily intake of most ARGs via aquaculture products was higher than those via PM2.5 and drinking water, but lower than that via vegetables. The relative abundances of MGE (IS613, Tp614, tnpA and int1) were significantly correlated with those of multiple ARGs, indicating the horizontal gene transfer (HGT) of ARGs among gut microorganisms. Proteobacteria, Firmicutes and Actinobacteria were the dominated microbial communities found in the guts of aquaculture products. In addition, significant correlations were found between Cyanobacteria and int1, between Nitrospira and tetE, and between sul2 and aadA2, indicating potential same hosts of these genes. In addition, results from co-correlation indicated both HGT (dominated by MGEs) of ARGs and the enrichment of ARGs in bacteria. MGEs, mostly int1, were more effective than bacteria in increasing the ARG abundance. This study could provide a better understanding of the transmission of ARGs in the aquaculture environment and improve the quality of aquaculture products and the ecology.KEYWORDS: Antibiotic resistance genesguts of aquaculture productsfreshwater pondshorizontal gene transferthe enrichment of ARGs in bacteria Data availability statementThe authors confirm that the data supporting the findings of this study are available within the article [and/or] its supplementary materials.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by Science and Technology Commission of Shanghai Municipality [grant number 21002410500, 22dz1202602, and 20DZ2250700]; Shanghai Science and Technology Development Fund; Shanghai Municipal Commission of Agriculture and Rural Affairs [grant number X20210301]; Science and Technology Commission of Shanghai Municipality.