[Typing of Listeria monocytogenes in import and export foods with PFGE].
OBJECTIVE
To investigate the molecular type and genetic correlation of Listeria monocytogenes (LMO) isolated from imported and exported foods.


METHODS
Pulsed-field gel electrophoresis (PFGE) standard method recommended by american PulseNet for typing LMO was applied. The chromosomal DNA of L. monocytogenes was digested by restriction enzyme Asc I and analyzed by PFGE. The PFGE patterns of L. monocytogenes strains isolated from different areas were compared by using BioNumberics software to analyze the similarity between strains.


RESULTS
Twenty-four L. monocytogenes strains were grouped into 20 PFGE subtypes by the similarity of PFGE pattern ranged from 44.45% to 100%. Particularly, it was identified that there were three subtype strain groups, each group sharing with the same PFGE pattern, and the similarity reaching 100%: the first group including LMO16 from Canada, LMO18 from America and LMO13 from Denmark, the second group including LMO7 from Denmark and LMO22 from Shunde, and the third group including LMO21 from Guangzhou and LMO8 from Shanxi.


CONCLUSIONS
Generally, much genetic diversity was shown in Listeria monocytogenes isolated from import and export foods, but the correlations among strains are existed to some extent.
Xu
Longyan
L
Food Laboratory of Technology Center, Guangdong Entry-Exit Inspection and Quarantine Bureau, Guangzhou 510623, China.
Yuan
Muyun
M
Liu
Jingyu
J
Zhao
Guiming
G
Zou
Zhifei
Z
Ling
Li
L
Zhang
Wang
W
Jiao
Hong
H
D015373:Bacterial Typing Techniques / Q000379:methods; D004269:DNA, Bacterial / Q000032:analysis; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D008089:Listeria monocytogenes / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
D004269:DNA, Bacterial