title: The role of class I integrons in the dissemination of sulfonamide resistance genes in the Pearl River and Pearl River Estuary, South China.
abstract: Antibiotic resistance genes (ARGs), as a newly emerging contaminant, are unique because they are disseminated through horizontal gene transfer in the environment. In the present study, a class 1 integron gene (int1) and various ARGs (sul1, sul2, sul3, qnrS, and ermB) were measured in water and sediment samples from the Pearl River (PR) to the Pearl River Estuary (PRE), where there is a distinct gradient in anthropogenic impact. The int1, sul1, and sul2 genes were detected in all samples, and their concentrations exhibited a clear trend of decline consistent with anthropogenic impact. Both the int1 and sul genes had dynamically migrated between water and sediments. The relative abundance of the int1 gene normalized to the 16S rRNA gene correlated significantly with the total concentrations of antibiotics in water and sediments. Good correlations were also observed between the abundance of int1 and each type of sul gene in the samples. However, the sul1 gene showed a much stronger relationship with int1 in different seasons, probably due to the presence of sul1 in the conserved region of class 1 integron. Our results strongly support that integrons play an important role in the dissemination of ARGs in human-impacted aquatic environments.
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; School of Marine Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Baowei
authors.initials: B
authors.lastname: Chen
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China.
authors.forename: Ximei
authors.initials: X
authors.lastname: Liang
authors.affiliation: Department of Ecology/Institute of Hydrobiology, Jinan University, Guangzhou 510632, China.
authors.forename: Xiangping
authors.initials: X
authors.lastname: Nie
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Huang
authors.affiliation: School of Marine Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Shichun
authors.initials: S
authors.lastname: Zou
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. Electronic address: cexdli@polyu.edu.hk.
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Li
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis*; D001426:Bacterial Proteins / Q000235:genetics; D002681:China; D004269:DNA, Bacterial / Q000032:analysis; D004352:Drug Resistance, Microbial / Q000235:genetics*; D063366:Estuaries; D005798:Genes, Bacterial; D019015:Geologic Sediments / Q000032:analysis; D032023:Integrons; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D045483:Rivers; D013449:Sulfonamides / Q000032:analysis*; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D013449:Sulfonamides; D014873:Water Pollutants
keywords: Antibiotic resistance genes (ARG); Class 1 intergron, Pearl River Estuary (PRE); South China; Sulfonamide resistance genes (sul1, and sul2)