[Application of pulsed-field gel electrophoresis typing in tracing and carrying out surveillance programs on O139 cholera outbreaks].
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.
Liu
Hong-lu
HL
Sichuan Provincial Center for Disease Control and Prevention, Chengdu 610031, China.
Zhang
Jing-yun
JY
Feng
Ze-hui
ZH
Li
Wei
W
Cui
Zhi-gang
ZG
Zhang
Li-juan
LJ
Zhu
Xiao-ping
XP
Kan
Biao
B
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
D002772:Cholera Toxin