Study On Serotyping, Molecular Characteristics And Sourcing Of Vibrio Parahaemolyticus Isolated From Guangdong Province From 2004 To 2007

ObjectiveThis research mainly aimed at studying the serotypes,molecular characteristics and sources-tracking of the vibrio parahaemolyticus(VP) food poison strains and aquatic products isolates in 2004～2007 in Guangdong Province by serotyping,virulence factors detecting and ERIC-PCR(enterobacterial repetitive intergenic consensus sequence PCR).The epidemiological relationship will be analyzed between food poison strains and aquatic products strains in molecular level,for further providing scientific evidence on prevention and control of VP foodborne disease.MethodsFirstly,275 VP isolates from food-poisoning patients and aquatic products were recovered and identified.Then slide serum agglutination.Secondly,The serotype,toxicity genes(tdh and trh) and genotyping of above strains were detected by using serotype,PCR and ERIC-PCR. Thirdly,the genetic relationships of the strains were analyzed by using un-weighted pair-group mean arithmetic(UPGMA) of the software BioNumerics V4.0 to carry on the cluster analysis.Results1.Totally 275 VP strains were recovered and identified.The results of identification matched with the initial identification.Among 156 food poison strains,19 serotypes were isolated and 143 strains were fully typed with the total-rate of 91.67%,the dominant type was O3:K6 which occurred 76.92%(120/156).Among 119 aquatic products strains,50 serotypes were isolated and 57 strains were fully typed with total-rate of 47.90%.Although it was showed that 119 aquatic products strains concentrated in 7 serum groups as O 1,O2,O3,O4,O5,O10, O11,no major popular type was observed.2.275 VP strains were conducted tdh,trh and urease tests.The results from food poison isolates demonstrated that tdh was positive in most of food poison isolates with the rate was 98.07%(153/156),while trh was only 2.56%(4/156) positive in above strains;Meanwhile the tdh positive only occurred 1.68%(2/119)and trh was negative in all aquatic products isolates; Otherwise,urease tests were positive in all trh positive isolates.3.275 VP strains were typed into 92 genotypes by ERIC-PCR with the features of the number of bands ranged from 3 to 16,molecular sizes from 50 to 3000kb in length and the similarity values from 41.3%to 100%.It was found that no significant correlation among the isolated years,the areas and the serotype of the strains no matter in the food poison isolates or aquatic products isolates at the aspect of.ERIC-PCR was applied to analyzed the souce trace of 2 VP food-poisoning events in 2008.It was suggested that ERIC-PCR was an effective technology for souce-trace.Conclusion1.The serotypes were different between food poison strains and aquatic products isolates.The main serotype of VP food poison strains in Guangdong Province from 2004 to 2007 was O3:K6,but no prevalent serotype was seen in aquatic products isolates.The manifestations of path VP toxicity genes were tdh positive and trh negative in Guangdong Province from 2004 to 2007.No significant correlation was appeared between tdh gene and serotype,but trh gene was mainly related to O1:KUT strains.2.It is suggested that multiple genetypes co-exist with obvious inherit multiformity in VP strains of Guangdong Province from the year of 2004 to 2007.ERIC-PCR can be applied in souce-tracing,providing effectively technical support for prevention and control of food-poisoning events.