Isolation and identification of a pathogenic bacterium associated with off plate syndrome from Apostichopus japonicus cultured in Liaoning Province

Abstract:

The off plate syndrome is an epidemic disease of juvenile sea cucumber Apostichopus japonicus during nursery period, showing severe infection, rapid transmission and high mortality. In this study, epidemiological investigation of off plate syndrome was conducted in several infected hatcheries along the coast of Liaoning Province. A dominant bacteria strain coded Aj2010072802A90 was isolated from the skin of affected juveniles and proved to be the pathogen through the artificial infection tests. The pathogen was identified as Vibrio parahaemolyticus through morphological observation, physiological & biochemical tests and 16S rDNA sequence analysis. This is the first report on V. parahaemolyticus disease in juvenile sea cucumber. Drug sensitive tests were done against the pathogen and revealed that the V. parahaemolyticus strain was sensitive to florfenicol. The result would provide theoretical basis and technical support for disease control and health management in sea cucumber culture.