Molecular Characteristics and Changes of Serotypes of Vibrio parahaemolyticus in Xixiang Street in Shenzhen in Recent Five Years

Objective To investigate the distribution of the serotypes of Vibrio parahaemolyticus inducing infectious diarrhea in Xixiang street,Baoan District of Shenzhen in the recent five years and to explore its virulence factors and molecular epidemiological characteristics,so as to provide basis for the early warning and forecast of the epidemic outbreak.Methods The serotypes of the isolates of Vibrio parahaemolyticus were identified by traditional serum agglutination assay.The virulence genes were detected by fluorescence PCR.Molecular typing was performed by pulse field gel electrophoresis(PFGE),and cluster analysis was made on the PFGE maps by BioNumerics software.Results Totally 1,077 targeted pathogenic bacteria were detected from 4,825 specimens,among which Vibrio parahaemolyticus accounted for 79.01%(851/1,077).The predominant serotype of Vibrio parahaemolyticus in this area was O3:K6(66.15%),and serotype O4:K8 came next(10.34%).93.4%(795/851) of the strains had the virulence gene pattern of tdh+tlh+trh-.PFGE analysis of 60 strains of O3:K6 type Vibrio parahaemolyticus found 20 different maps,and the difference among them was confined to three bands.Conclusions O3:K6 type is the predominant serotype of Vibrio parahaemolyticus in Xixiang Street in Shenzhen.93.4% of the strains carry tdh+tlh+trh-.The isolates have homology.