Virulence characterization and genotypic analyses of Listeria monocytogenes isolates from food and processing environments in eastern China.
In this study, twenty L. monocytogenes food-related isolates collected from eastern China Zhejiang province were compared by in vivo LD50 assays as well as in vitro cytopathic plaque forming assay. Nineteen L. monocytogenes isolates (19/20) were as virulent as reference strain 10403S, while the isolate M4 had low pathogenicity. The unique isolate M4 fell into lineage III based on the partial nucleotide variations of actA, while the other isolates belonged to the more common lineages I and II. L. monocytogenes isolates were grouped in 17 to 19 subtypes using pulsed-field gel electrophoresis (PFGE) with SmaI digestion, and multilocus sequence typing (MLST) based on three virulence genes (actA, inlA and inlB) and four housekeeping genes (betL, dat, recA and sigB). The virulence genes based MLST had better discriminatory power than that targeting the housekeeping genes (0.990 vs 0.895), similar to PFGE (0.976). An isolate from the processing desk was found having the same pulsotype as the two isolates from final shrimp products in the same plant, indicating that process contamination could be the source of Listeria contamination.
Zhejiang University Institute of Preventive Veterinary Medicine, PR China.
Lingli
L
Jiang
Jianshun
J
Chen
Jingjing
J
Xu
Xiaofeng
X
Zhang
Shuna
S
Wang
Huancan
H
Zhao
Khamphouth
K
Vongxay
Weihuan
W
Fang
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002642:Chick Embryo; D002681:China; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D005525:Food-Processing Industry; D005517:Foodborne Diseases / Q000382:microbiology; D005838:Genotype; D006801:Humans; D007928:Lethal Dose 50; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D008088:Listeriosis / Q000382:microbiology; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008565:Membrane Proteins; D037521:Virulence Factors; C072980:actA protein, Listeria monocytogenes