title: [Application of pulsed-field gel electrophoresis typing in tracing and carrying out surveillance programs on O139 cholera outbreaks].
abstract: OBJECTIVE
  To study the characteristics of molecular typing and phylogenic relationship among the Vibrio cholerae serogroup O139 strains isolated from environment and sea food samples during cholera outbreaks, in Sichuan province in 2004 and to trace the source of infections so as to support the ascertainment of epidemic control strategy.
  
  
  METHODS
  Cholera toxin gene was detected by polymerase chain reaction amplification. Pulsed-field gel electrophoresis (PFGE) was used for subtyping of isolates and clustering of patterns was analysed with the software BioNumerics.
  
  
  RESULTS
  In all the 72 strains under analysis, 68 appeared to be toxigenic while 4 from river water derived isolates were toxin gene negative. Sixty-seven strains were clustered into 16 PFGE patterns when digested with Not I. The patterns of toxigeinc O139 strains isolated from turtles in the markets were identical with the patterns of strains appeared in the outbreaks respectively. The PFGE patterns of isolates from different outbreaks were inconsistent.
  
  
  CONCLUSIONS
  The sources of infection causing these outbreaks were complicated. Contaminated turtles might also be one of the major sources of outbreaks when being served at the dinner parties in Sichuan in 2004.
authors.affiliation: Sichuan Provincial Center for Disease Control and Prevention, Chengdu 610031, China.
authors.forename: Hong-lu
authors.initials: HL
authors.lastname: Liu
authors.forename: Jing-yun
authors.initials: JY
authors.lastname: Zhang
authors.forename: Ze-hui
authors.initials: ZH
authors.lastname: Feng
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Zhi-gang
authors.initials: ZG
authors.lastname: Cui
authors.forename: Li-juan
authors.initials: LJ
authors.lastname: Zhang
authors.forename: Xiao-ping
authors.initials: XP
authors.lastname: Zhu
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques / Q000379:methods*; D002681:China / Q000453:epidemiology; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission; D002772:Cholera Toxin / Q000235:genetics; D016000:Cluster Analysis; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005516:Food Microbiology; D006801:Humans; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011159:Population Surveillance; D012984:Software; D014426:Turtles / Q000382:microbiology; D041242:Vibrio cholerae O139 / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D014871:Water Microbiology
chemical_list: D002772:Cholera Toxin