Epidemiology,Antibiotic Susceptibility Test And Virulence Gene Detection Of Vibrios Islotated From Shellfish In Shandong Province

In recent years,species and breeding of shellfish aquaculture are increasingly diversified,and the technology of breeding matures gradually.Meanwhile,farming area is gradually expanding.The production of China's aquaculture shellfish also increased gradually.However,The losses caused by microorganisms with Vibrio as the main pathogen to shellfish aquaculture industry should not be underestimated.Usually,July and August in summer are the seasons of high prevallence of shellfish diseases.The aquatic diseases caused by vibriate are characterised by widespread area,high prevallence,causing serious losses to the aquaculture industry,and have always been a hot research field.Our experiments investagated the shellfish culture area in coastal areas of Shandong Province.The results are as follows:Different shellfish were collected in Shouguang county of Weifang city,Rushan county of Weihai city,Jiaonan county of Qingdao city,Wudi county of Binzhou city and Hekou county of Dongying city.The isolated Vibrio was identified by bacterial isolation,cloning of 16s-rDNA and sequence analysis.Including a variety of marine shellfish.Twenty-seven species of Vibrio and eight pecies of other bacteria were isolated from the sample.Sequencing analysis,including Vibrio harveyi,Vibrio alginolyticus,Vibrio parahaemolyticus,Vibrio chagasii,Vibrio azureus,Vibrio natriegens,Vibrio vulnificus,Vibrio hangzhouensisand so on.According to the results of the survey,Vibrio vulgaris,Vibrio alginolyticus,Vibrio parahaemolyticus in the shellfish there are more,respectively,20%,18%,21%;other Vibrio relatively less.There were more Vibrio parahaemolyticus and Vibrio alginolyticus in Jiaonan area;in Wudi Vibrio harveyi and Vibrio alginolyticus are more,while Vibrio parahaemolyticus is few;Hekou Rizhao Shouguang these three regions,three kinds of Vibrio detection rate are relatively high,are between 15%-35%.According to the survey results show that Vibrio is one of the major pathogens causing shellfish disease,serious damage to marine shellfish.Among them,Vibrio vulgaris,Vibrio parahaemolyticus and Vibrio alginolyticus were isolated.Different Vibrio in different shellfish detection rate is very different,in different regions in the detection rate is also very different.According to the results of the survey,a relatively small number of three strains of Vibrio were tested for susceptibility testing,including Vibrio harveyi,Vibrio parahaemolyticus and Vibrio alginolyticus.Drugs include: amikacin,gentamicin,naphthacetic acid,ciprofloxacin,norfloxacin,erythromycin,azithromycin,tetracycline,doxycycline,cefalotin,cefuroxime,enova Star,florfenicol,ampicillin,piperacillin,amoxicillin,cotrimoxazole these drugs.According to the experiment,these three kinds of Vibrio are resistant to ampicillin and amoxicillin,the sensitivity of other drugs is different,there are resistant bacteria appear.In this study,the main virulence genes of Vibrio harveyi and Vibrio parahaemolyticus were detected,The main virulence of Vibrio harveyi include luxR?toxR?vhhA?vhhB?vhpA?vhpB?toxS?flaA?pap6.The results showed that luxR,toxR,vhhA,vhhB were detected in80% of Vibrio harveyi.The main virulence genes of Vibrio parahaemolyticus were tdh,trh,ureC,vscC2,vcrD2.Among them,tdh,trh and ureC were detected in 20% strains.From this investigation,we can know the prevalence of shellfish diseases caused by Vibrio in coastal areas of Shandong province,early warning of disease;Through the test of resistance to Vibrio parahaemolyticus,Vibrio parahaemolyticus and Vibrio parahaemolyticus,rational use of antibiotics to prevent the disease of Vibrio,provides a theoretical basis for clinical guidance.