Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, Minato-ku, Tokyo, Japan.
J Microbiol Methods. 2012 Sep;90(3):285-91. doi: 10.1016/j.mimet.2012.05.023. Epub 2012 Jun 5.
Tandem repeats (TR), which are repetitive nucleotide sequences in DNA, are polymorphic both in repeat number and sequence. In this study, we developed a new typing method, multilocus TR sequence analysis (MLTSA), for the foodborne pathogen Listeria monocytogenes using sequence polymorphisms in three tandem repeat regions. The obtained dendrogram clustered L. monocytogenes strains of lineage I and lineage II separately, and formed three groups within the lineage I cluster, each of which included one of the three major L. monocytogenes epidemic clones (ECI, ECIa, and ECII). These results were consistent with a previously established virulence-gene-based MLST method. In comparison, our method grouped some epidemiologically related isolates together, which virulence-gene-based MLST did not. Moreover, our method, using three tandem repeat regions, showed a higher discriminatory power than the MLST method, which uses six virulence gene regions. This MLTSA approach using sequence polymorphisms in TR regions could be a useful tool in the epidemiological study of L. monocytogenes.
串联重复（TR）是 DNA 中的重复核苷酸序列，在重复数量和序列上都具有多态性。在这项研究中，我们使用三个串联重复区域中的序列多态性，为食源性致病菌单核细胞增生李斯特菌开发了一种新的分型方法，即多位点 TR 序列分析（MLTSA）。得到的聚类树将谱系 I 和谱系 II 的单核细胞增生李斯特菌菌株分开聚类，并在谱系 I 聚类内形成三个组，每个组都包含三个主要的单核细胞增生李斯特菌流行克隆（ECI、ECIa 和 ECII）之一。这些结果与先前建立的基于毒力基因的 MLST 方法一致。相比之下，我们的方法将一些具有流行病学相关性的分离株聚集在一起，而基于毒力基因的 MLST 方法则没有。此外，我们的方法使用三个串联重复区域，比使用六个毒力基因区域的 MLST 方法具有更高的分辨能力。这种使用 TR 区域序列多态性的 MLTSA 方法可能是单核细胞增生李斯特菌流行病学研究的有用工具。
