The etiologic characteristics of Vibrio cholerae in Guangdong province in 2007 / 中华流行病学杂志

ABSTRACT

Objective To analyze the etiologic characteristics of Vibrio cholerae in Guangdong province in 2007.Genetic relationship was observed including among predominated biotype isolates from different areas within the province and among same biotypes isolates from cholera cases and regular surveillance.Methods Isolates from cholera cases and through environmental surveillance were typed by sero-and phage-typings.Similarity of molecular fingerprinting was analyzed through comparing the pulsed field gel electrophoresis(PFGE)pattern of predominated biotype isolates,and those of the same biotype isolates from cholera cases and environment surveillance,respectively.In addition,genetic relationship was determined by clustering analysis,using bionumerics software.Results In total,31 isolates from cholera cases were collected and subtyped for 3 serogroups.V.cholerae O1 El Tor Inaba phage 1d was the predominant biotype which causing most of the cases in Guangdong province in 2007.Data from cluster analysis showed that the similarity among Inaba phage 1d strains from different areas were from 94.5% to 100%.However.16 isolates were collected from environment surveillance programs and the predominated biotype could not be found.Additionally,the biotype distribution of cases isolates was not consistent with those isolates through surveillance.High phylogenetic diversity was observed for the same biotypes isolates from cases and surveillance samples.Conclusion Our data showed that V.cholerae O1 El Tor Inaba phage 1d was the predominated biotype with multi-clone coexisting and circulating in Guangdong province in 2007.It also appeared to be the characteristics of cholera in the non-epidemic period,suggesting that it was necessary to enhance the alert surveillance programs for cholera epidemic based on the molecular typing techniques.