Open AccessIdentification and Detection of the Pathogenic Bacteria Responsible for Swollen Abdomen Disease in Cultured Turbot, Scophthalmus maximus , and Flounder, Paralichthys olivaceus
Author(s) -
Xue Shuxia,
Sun Jinsheng,
Xu Wei
Publication year - 2018
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/jwas.12435
Subject(s) - edwardsiella tarda , biology , vibrio alginolyticus , microbiology and biotechnology , turbot , olive flounder , scophthalmus , paralichthys , 16s ribosomal rna , polymerase chain reaction , multiplex polymerase chain reaction , multiplex , bacteria , vibrio , gene , fishery , genetics , fish <actinopterygii>
Abstract Swollen abdomen disease ( SAD ) seriously threatens the aquaculture of turbots and flounders. Two dominant bacterial strains, FS1 and FS2 , were isolated from the livers and kidneys of fish with diagnosed SAD . Applications of biochemical analyses, sequence analyses of 16S ribosomal RNA gene and heat shock protein 60 gene revealed two distinct pathogenic bacterial species, Edwardsiella tarda and Vibrio alginolyticus . These two hypothesized SAD ‐causing pathogens were validated by challenge trials on flounder, Paralichthys olivaceus . Challenges with E. tarda and V. alginolyticus demonstrated lethal dose 50 ( LD 50 ) values at 1.51 × 10 5 colony‐forming units ( CFU ) and 1.05 × 10 5 CFU , respectively. To develop a rapid SAD diagnosis method in flounders and turbots, a multiplex polymerase chain reaction ( PCR ) assay method was developed to simultaneously detect E. tarda and V. alginolyticus . Our multiplex PCR assay successfully detected as low as 10 5 CFU /mL E. tarda and V. alginolyticus in flounders and turbots. No other common fish pathogens were detected with the multiplex PCR , suggesting a high specificity of this assay. The multiplex PCR assay developed in this study showed a great reliability in detecting SAD ‐causing bacterial pathogens. Further optimization of this assay may contribute to the development of a novel SAD diagnosis tool in aquaculture.