Detection And Analysis Of Pathogenic Bacteria And Study On Virulence And Drug Resistance Of Vibrio Parahaemolyticus And Salmonella In Aquatic Products And Raw Poultry Meat

Deputy vibrio parahaemolyticus,Salmonella and other bacteria in aquatic products and poultry are the main pathogenic bacteria that cause collective cases of food poisoning.In this paper,five kinds of pathogenic bacteria in aquatic products and two kinds of pathogenic bacteria in poultry were analyzed.60 strains of vibrio parahaemolyticus and 40 strains of Salmonella were isolated,and biochemical identification and serotyping,and detected the virulence gene\carrying status of the isolated strains were performed.Ampicillin and other 20antimicrobial agents were used to test the drug sensitivity of the isolates,and the drug resistance of isolates was analyzed.1.In this study,pathogenic bacteria were isolated and identified from aquatic product samples and raw poultry meat collected from local markets in the city of south China.The detectable rate of vibrio parahaemolyticus in aquatic products was 13.82%,and was found at the highest in fish.The detectable rate of Salmonella was 7.33%.In addition,Salmonella was only detected in fish and was absent in crab,shellfish,shrimp.The detectable rate of Staphylococcus aureus was 17.91%,whereas the detectable rate of Listeria monocytogenes was0.79%.The detectable rate of E.coli was 26.92%.The detectable rate of Salmonella in raw poultry meat was 21.13%,but there was no significant difference between the detectable rate in raw chicken and that in duck.2.Biochemical characteristics,virulence gene carrying status and drug resistance rate of60 vibrio parahaemolyticus strains isolated from aquatic samples were analyzed.The main results were as follows:(1)Results of biochemical analysis showed that results of H₂S and sucrose tests were both negative and that of glucose test were positive,which was consistent with typical biochemistry of vibrio parahaemolyticus.The positive rate of lysine decarboxylase test was different from that of conventional biochemical test.(2)The genotypes of virulence genes were analyzed and we found that all the isolates carried tlh and tox R/S genes,with a carrying rate of 95.00%for tdh and 65.00%for trh.The carrying rate of four major virulence genes carried rate was 61.67%.(3)Results of drug resistance showed that all 60 strains were highly resistant to ampicillin,with drug resistance rate exceeding 95.00%.Multi-drug resistance was not prominent.Only 4strains,mainly from fish,were resistant to 2 drugs.3.Biochemical characteristics,serotyping,virulence gene carrying status and drug resistance rate of 40 Salmonella strains isolated from raw poultry meat and fish were analyzed.The main results were as follows:(1)Results of biochemical analysis showed that results of H₂S test and other 13 tests were consistent with typical biochemistry of Salmonella.Only one strain was negative for a-galactosidase test and showed a different probability from that of conventional biochemical test.(2)Results of the blood type analysis showed that Salmonella Corvallis was accounted for the most cases,with 9 strains detected,followed by Salmonella Derby,Salmonella Infantis,Salmonella Rissen and Salmonella Kentucky.(3)By analyzing the carrying status of 29 virulence genes,it was found that the detectable rate of inv A,hil A,sop B,tol C,spi A,stn were the highest among all virulence genes(above90.00%).The detectable rate of sef A,sop E,org A,iro N,gtg B and other virulence genes were lower(below 10.00%).Multi-toxicity was prominent,with 12 strains carrying 21 or more virulence genes and 35 strains carrying 10 or more virulence genes.(4)Results of drug resistance analysis indicated that the isolated strains showed extremely high resistance to 7 antibacterial drugs,namely cefazolin,cefuroxime,cefuroxime ester,ceftetan and aminoglycoside amikacin,gentamicin and tobramycin,with drug resistance rate of 100%.Strains were more sensitive to piperacillin/tazobactam,imipenem,ceftazidime,cefepime,ciprofloxacin,levofloxacin 6 kinds of antibacterial drugs.Multi-drug resistance was prominent,with 12 Salmonella strains carrying 21 or more virulence genes showing 7 or more muti-drug resistance.