[Molecular typing of Listeria monocytogenes isolated from foodstuff in Guangdong province by pulsed-field gel electrophoresis].
OBJECTIVE
To establish molecular typing of Listeria monocytogenes isolates by pulsed-field gel electrophoresis (PFGE) for studying the epidemiologic characteristics of Listeria monocytogenes isolated from foodstuff in Guangdong province and to build up PFGE typing database of Listeria monocytogenes isolates for identifying the infectious resource of the outbreaks and other epidemiologic investigation.


METHODS
"Standardized Protocol for Molecular Subtyping of Listeria monocytogenes by PFGE" was followed. BioNumerics software was applied on image analysis, database establishment, comparative and corresponding analysis.


RESULTS
107 Listeria monocytogenes isolates were typed by PFGE, 41 PFGE types were observed among the isolates. The PFGE types were dispersive among these isolates. Listeria monocytogenes isolates were most frequently isolated in raw chicken while the most PFGE types were found in this type of food. The positive rate was relatively high in cold and iced foods. Only 1-2 DNA fragment difference occurred in 26 Listeria monocytogenes isolates by PFGE, so high degree of relatedness remained among these isolates. There were unique PFGE patterns in the regions of Shaoguan and Huizhou. From time to time, a number of isolates remained close relationship.


CONCLUSIONS
PFGE typing of the 107 Guangdong Listeria monocytogenes isolates demonstrated relative genetic diversity but a number of the isolates showed close relatedness.
He
Dong-mei
DM
Institute of Microbiology, Guangdong Province Center for Disease Control and Prevention, Guangzhou 510300, China.
Deng
Feng
F
Wang
Hong-min
HM
Ke
Chang-wen
CW
Yan
Ji-wen
JW
Zhu
Hai-ming
HM
Lai
Wei-dong
WD
Song
Man-dan
MD
Yang
Bing
B
Wang
Hai-yan
HY
Wang
Jian
J
Cong
Ma
M
Ke
Bi-xia
BX
Deng
Xiao-ling
XL
Ni
Han-zhong
HZ
D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods*; D005516:Food Microbiology; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D010802:Phylogeny