title: Genetic variation of Listeria monocytogenes isolates from domestic and imported foods in Japan.
abstract: Phylogenetic analyses were carried out on a total of 118 Listeria monocytogenes isolates from foods or food processing environments, and 7 isolates from listeriosis patients in Japan to evaluate the genetic variation in the pathogen in this country. Isolates of serotypes 1/2a, 1/2b and 4b were mainly examined to assess the risk of exposure of humans to L. monocytogenes from foods in Japan. The nucleotide sequences of the part of the iap gene that contains the region encoding the threonine-asparagine repeat units were determined in order to construct phylogenetic trees of the isolates investigated. A phylogram showed high genetic diversity among lineage 2 isolates, while the lineage 1 isolates showed clonal characteristics. The results of the genetic analyses suggested the presence of rare putative lineage 3 isolates and epidemic clone I (ECI) isolates in foods in Japan. The results showed that ECI was also isolated from listeriosis patients. The genetic variation in L. monocytogenes in Japan reported here suggests the necessity of monitoring the pathogen in foods and environments in addition to surveillance of listeriosis patients.
authors.affiliation: Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Sciences University, Tokyo 180-8602, Japan. yochiai@nvlu.ac.jp
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Ochiai
authors.forename: Otgonchimeg
authors.initials: O
authors.lastname: Batmunkh
authors.forename: Kunitoshi
authors.initials: K
authors.lastname: Ogasawara
authors.forename: Mariko
authors.initials: M
authors.lastname: Mochizuki
authors.forename: Ryo
authors.initials: R
authors.lastname: Hondo
authors.forename: Fukiko
authors.initials: F
authors.lastname: Ueda
mesh_terms: D001483:Base Sequence; D003257:Consumer Product Safety; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000382:microbiology; D005784:Gene Amplification; D014644:Genetic Variation; D006801:Humans; D007564:Japan; D008089:Listeria monocytogenes / Q000145:classification* / Q000235:genetics* / Q000472:pathogenicity; D008088:Listeriosis / Q000382:microbiology; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial