Miya Satoko, Takahashi Hajime, Nakagawa Miku, Kuda Takashi, Igimi Shizunobu, Kimura Bon
Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, Tokyo, Japan.
Division of Biomedical Food Research, National Institute of Health Sciences, Tokyo, Japan.
PLoS One. 2015 Mar 31;10(3):e0122902. doi: 10.1371/journal.pone.0122902. eCollection 2015.
Listeria monocytogenes causes foodborne illnesses through consumption of ready-to-eat foods. Although 135-201annual listeriosis cases have been estimated in Japan, the details regarding the clinical isolates such as infection source, virulence level, and other genetic characteristics, are not known. In order to uncover the trends of listeriosis in Japan and use the knowledge for prevention measures to be taken, the genetic characteristics of the past human clinical isolates needs to be elucidated. For this purpose, multilocus tandem-repeat sequence analysis (MLTSA) and multi-virulence-locus sequence typing (MVLST) were used in this study. The clinical isolates showed a variety of genetically distant genotypes, indicating they were from sporadic cases. However, the MVLST profiles of 7 clinical isolates were identical to those of epidemic clone (EC) I isolates, which have caused several serious outbreaks in other countries, suggesting the possibility that they have strong virulence potential and originated from a single outbreak. Moreover, 6 Japanese food isolates shared their genotypes with ECI isolates, indicating that there may be risks for listeriosis outbreak in Japan. This is the first investigational study on genetic characteristics of Japanese listeriosis isolates. The listeriosis cases happened in the past are presumably sporadic, but it is still possible that some isolates with strong virulence potential have caused listeriosis outbreaks, and future listeriosis risks also exist.
单核细胞增生李斯特菌通过食用即食食品引发食源性疾病。尽管据估计日本每年有135 - 201例李斯特菌病病例，但关于临床分离株的详细情况，如感染源、毒力水平和其他遗传特征，尚不清楚。为了揭示日本李斯特菌病的流行趋势并将这些知识用于采取预防措施，需要阐明过去人类临床分离株的遗传特征。为此，本研究采用了多位点串联重复序列分析（MLTSA）和多毒力位点序列分型（MVLST）。临床分离株显示出多种遗传距离较远的基因型，表明它们来自散发病例。然而，7株临床分离株的MVLST谱与在其他国家引发多次严重疫情的流行克隆（EC）I分离株相同，这表明它们可能具有很强的毒力潜力且源自单一疫情。此外，6株日本食品分离株与ECI分离株具有相同的基因型，这表明日本可能存在李斯特菌病暴发的风险。这是关于日本李斯特菌病分离株遗传特征的首次调查研究。过去发生的李斯特菌病病例据推测是散发性的，但仍有可能一些具有强毒力潜力的分离株引发了李斯特菌病疫情，并且未来也存在李斯特菌病风险。
