title: [Molecular typing of isolates from two dysentery outbreaks in Chengdu, through pulsed field gel electrophoresis technology].
abstract: OBJECTIVE
  Using pulsed field gel electrophoresis (PFGE) and polymerase chain reaction (PCR) typing to analyze strains isolated from two outbreaks caused by Shigella sonnei and to trace the source of infection.
  
  
  METHODS
  Virulence genes ipaH and ial were detected by PCR and PFGE was used to subtype the isolates. Patterns were compared, using the software BioNumerics.
  
  
  RESULTS
  Within the 54 isolates, all were ipaH positive with 48 as ial positive. Strains from the Chongzhou outbreak were clustered into 4 PFGE patterns, with the predominant pattern accounted for 72% of the analyzed strains. The pattern of strains isolated from the cold pork with sauce was identical to the predominant pattern. The strains from Dayi outbreak were clustered into 8 PFGE patterns and the predominant pattern accounted for 56% of the test strains.
  
  
  CONCLUSIONS
  Strains from the two outbreaks were quite different and the 'cold pork with sauce' seemed to be the major source of infection, causing the outbreak of diarrhea in Chongzhou. The sources of infection of the Dayi outbreak might be complicated whereas PFGE showed a discriminatory and reproducible laboratory tool in the epidemiologic investigation on outbreaks of diarrhea.
authors.affiliation: Chengdu Municipal Center for Disease Control and Prevention, China.
authors.forename: Yan-Fang
authors.initials: YF
authors.lastname: Miao
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Huang
authors.forename: Zhen-Jun
authors.initials: ZJ
authors.lastname: Li
authors.forename: Dong
authors.initials: D
authors.lastname: Jin
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Cui
authors.forename: Ai-Lan
authors.initials: AL
authors.lastname: Zhao
authors.forename: Na
authors.initials: N
authors.lastname: Liang
authors.forename: Yan
authors.initials: Y
authors.lastname: Bai
mesh_terms: D001434:Bacteriophage Typing; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D004405:Dysentery, Bacillary / Q000453:epidemiology* / Q000382:microbiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D012760:Shigella / Q000145:classification / Q000302:isolation & purification*