The Genetic Diversity And Ditribution Of Virulent Genes In Vibrio Alginolyticus Isolated From South China

Vibrio alginolyticus, a halophilic Gram-negative bacterium, inhabiting in marine andestuarine environments, is one of major Vibrio pathogens commun to human and marineanimals. V. alginolyticus is one main pathogen to various saltwater fishes, which causesthem wound infections, gastroenteritis and septicemia, and leads to large economic damage.Thus，it is essential to explore an effective protective pathway against the infection of thismicroorganism. Recently, the study of V. alginolyticus is involved with the biochemicalseparation and identification, the rapid detection by molecule methods, the moleculepolymorphism analysis with different source and phenotype of V. alginolyticus, theexpression and structural analysis of virulence proteins and so on. China has the longcoastline about32thousand kilometers, and the seafood is prevail in the southeastcoastland, especially, in the area of Fujian、Guangxi、Hainan and Guangdong province, butthe reports about food poisoning caused by V. alginolyticus are common occurance. So thedetection of V. alginolyticus with rapid and correct method is helpful to prevent thecontamination of V. alginolyticus. This assay analyzed the genotyping and the distributioncharacter of virulence genes in V. alginolyticus isolated from four different areas, they areFujian province, Guangxi province, Hainan province, Guangdong province. The objectiveis to help to establish the genomic fingerprinting, also new methods were developed to dectV. alginolyticus rapidly, and it will provide a platform to monitor and prevent the infectionof V. alginolyticus.1. We collected samples from culture areas in Fujian、 Guangxi、 Hainan andGuangdong, after biochemical identify and molecular biological identification,127strainsof Vibrio alginolyticus were obtained:34strains in Fujian,21strains in Guangxi,22strainsin Hainan snd50strains in Guangdong.2. To examine the genetic diversity of Vibrio alginolyticus which from breedingwaters in the south of China, we have isolated127Vibrio alginolyticus strains in the breeding waters from Fujian, Guangxi, Hainan and Guangdong, and the127strainsanalyzed by the RAPD technique. All of the Vibrio alginolyticus were grouped into23classes and total of164polymorphic loci were detected by the RAPD technique with10random primers. The Vibrio alginolyticus from Fujian breeding waters were grouped into11classes, from Guangxi were grouped into7classes, from Hainan were grouped into11classes, and from Guangdong were grouped into19classes. The cluster analysis showedthat the Vibrio alginolyticus from the same area share high similarity coefficient genotypesamong the strains, but share low similarity coefficient among the strains from the differentarea. This study may be important and helpful to the research of the epidemiology.3. To examine the distribution characteristics of virulence genes in V. alginolyticusisolated in the culture area of South of China. We collected water samples in the culturearea of Fujian、Guangxi、Hainan and Guangdong. After isolation and identification,127strains were obtained:34strains in Fujian,21strains in Guangxi,22strains in Hainan and50strains in Guangdong. Using PCR to detect the7virulence genes tlh、tdh、trh、toxR、sto、ctxA and vpi in these strains. There was no strain carrying tdh and trh, and thecarrying rate of toxR、tlh、sto、ctxA and vpi in127strain were100%、26.8%、22.8%、19.7%and15.7%. Overall, this study reveals the significant prevalence of V. alginolyticusin the culture area in the South of China, and their habits with high diversity of virulencegenes. Representative V. alginolyticus isolates could be used for further investigation intotheir pathongenecity, functional genomics, and molecular evolution.