Isolation and identification of Shewanella alga and its pathogenic effects on post-larvae of abalone Haliotis diversicolor supertexta.

摘要

This study reports on the isolation, identification and virulence of a pathogenic strain of S. alga (strain 27) isolated from diseased abalone post-larvae found in Shanwei, Guangdong Province, China in July 2003. To isolate the microorganisms from post larvae during disease outbreaks, 13 day old post-larvae together with their diatom films were transferred from the nursery ponds to the laboratory and placed in petri dishes. S. alga strain 27 was initially characterized using API 20E identification kits by comparing the reaction profile of strain 27 with S. alga type strain ATCC55627. The bacterial strain (27) isolated from diseased abalone post-larvae was a Gram-neagtive, motile, straight rod, which was oxidase positive, catalase positive and nonfermentive. It was also confirmed that strain 27 belongs to the Shewanella with 99.9% confidence. The results of 16rS rDNA sequencing reveals strain 27 shared 99.9% similarity with the type strain of S. alga. The 16S rDNA sequence was deposited in GenBank under accession number DQ026023..