Isolation and identification of pathogenic Aeromonas veronii isolated from infected Siberian sturgeon (Acipenser baerii)

Abstract:

Abstract: [Objective] Our study aimed at searching for the pathogenic factor causing Siberian sturgeon (Acipenser baerii) disease. [Methods] A pathogenetic bacterial strain X-1-06909 was isolated from naturally infected Siberian sturgeon in Beijing. The strain was identified according to its physiological and biochemical properties, and the sequence analysis of 16S rRNA gene. The drugs sensitivity was detected with Kirby-Bauer’s agar diffusion method. [Results] Based on the result of 16S rRNA sequence analysis，the strain X-1-06909 shares 99.6% sequence identity with the type strain ATTCC35624T of Aeromonas veronii.The morphological characteristics of the strain were gram-negative, polar single-flagella.The results of physiological and biochemical tests were that the strain could ferment glucose and produce gas , methyl red (M-R) and Voges-Proskauer (V-P) tests were positive, arginine dihydrolase test was negative, it grew on 3% sodium chloride culture medium, the tests for hydrolysis of gelatin and hydrolysis of esculin were negative. The result for drug sensitive tests showed that among 21 antibiotics, cefadroxil，neomycin etc. had better inhibitive effect on the strain. [Conclusion] The isolated strain X-1-06909 was identified as A. veronii. The results will provide evidences for further caring the diseases of sturgeons.