The Investigation Report Of The Healthy Freshwater Fish Carrying Aeromonas In ChangChun's Market For Sale

Aeromonas is a Gram-negative bacterium,a type of bacteria that is commonly found in aquatic ecosystems and is widely distributed throughout the world.These bacteria have a wide range of hosts.Not only can cause fish hemorrhagic sepsis and enteritis but also can cause human peritonitis,encephalitis,and a variety of suppurative diseases.In recent years,reports of ascites caused by Aeromonas and human diseases are increasing,and most pathogens are present in healthy animals.Therefore,there is great public health significance to investigate whether healthy animals carry the pathogenic of Aeromonas.This study was conducted to investigate the carrying status of commercially available freshwater fish.Four kinds of freshwater fish,carp,crucian carp,grass carp,and bream were selected for the study of four kinds of freshwater fish.The isolates were isolated by RS-identifying medium,and the isolates were cultured purely.Identification of phenotypic properties such as colony characteristics and physicochemical properties.The homology of 16 SrDNA and housekeeping gene gyrB gene was analyzed,and the homology of the corresponding sequence was analyzed.The results of ERIC-PCR were used to determine the species of Aeromonas in Changchun.Animal pathogenicity test of the isolates,as well as five major virulence genes for the isolates: aer,cytotoxic toxin,tryptophan,lip,aha for identification.A total of 94 strains of Aeromonas were isolated,including 67 strains of Aeromonas veronii,14 strains of Aeromonas sobria,7 strains of Aeromonas media,3 strains of Aeromonas salmonicida 1 strains of Aeromonas hydrophila.25 trains of grass crap,27 strains of crucian carp,23 strains of carp and 18 strains of bream were isolated from all the isolates.Animals were tested for all pathogenic strains.50.7% of the Aeromonas veronii isolateds' mice in the experimental group were dead in 72 hours,and 71.4% of the mice of the Aeromonas sobria also happened to die.At the same time,accounting for 22.3% of the total isolated strains carry all five kinds of virulence genes and 48.9% of the strains carrying four kinds of virulence genes.By means of the five virulence genes testing,92.6% of the strains carried aer,94.7% carried act,and 95.7% carried lip.Through the results of animal pathogenicity test for the isolated strians,the situation of carrying virulence genes and the pathogenicity of Aeromonas in Changchun were confirmed,and providing the theoretical basis to make the prevention of Aeromonas in Changchun.