Development of a multilocus variable-number of tandem repeat typing method for Listeria monocytogenes serotype 4b strains
Development of a multilocus variable-number of tandem repeat typing method for Listeria monocytogenes serotype 4b strains
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DOI：
10.1016/j.ijfoodmicro.2008.03.023
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发表时间：
2008-06-10
影响因子：
5.4
通讯作者：
Wiedmann, Martin
中科院分区：
文献类型：
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作者：
Miya, Satoko;Kimura, Bon;Wiedmann, Martin
单核细胞增生李斯特菌血清型4b菌株已被确定为许多人类淋病流行病以及相当数量的散发病例的病原体。由于血清型4b分离株的遗传同质性，需要开发对血清型4b分离株具有高区分能力的快速亚型分型方法，以改进暴发检测和来源追踪。在本研究中，开发了多位点可变数量串联重复分析（MLVA）并用于表征来自不同来源的60种血清型4b分离株。所有菌株的特征还在于自动化EcoRI核糖分型，单酶脉冲场凝胶电泳（PFGE）与Apal，和多位点序列分型（MLST）计划针对6个毒力和毒力相关基因。MLVA的辨别力（由Simpson辨别指数确定）高于其他三种方法的辨别力。发现靶向MLVA标记物稳定，并且当三种分离株每天传代70天时未发生变化。MLVA、PFGE和MLST的聚类分析一致地将相同的分离株分为三个主要的聚类，每个聚类包括三个主要的L。单核细胞增多症流行克隆（即，ECI、ECIa和ECII）。我们得出结论，这里描述的MLVA方法（i）提供了更多的区分L亚型。单核细胞增多症血清型4b菌株比其他三种方法，（ii）确定了血清型4b中的三个主要群体，这与其他亚型分型方法确定的群体一致。（三）易于理解。因此，建议使用MLVA对血清型4b分离株进行亚型分型，包括作为一种次要的更具区分性的亚型分型方法，可在通过PFGE或核糖分型进行初始分离株表征后使用。(C)2008 Elsevier B.V.保留所有权利。
Listeria monocytogenes serotype 4b strains have been identified as the Causative agent in many human listeriosis epidemics as well as in a considerable number of sporadic cases. Due to the genetic homogeneity of serotype 4b isolates, development of rapid subtyping methods with high discriminatory power for serotype 4b isolates is required to allow for improved Outbreak detection and source tracking. In this study multilocus variable-number tandem repeat analysis (MLVA) was developed and used to characterize 60 serotype 4b isolates from various Sources. All isolates were also characterized by automated EcoRI ribotyping, single enzyme pulsed-field gel electrophoresis (PFGE) with Apal, and a multilocus sequence typing (MLST) scheme targeting six virulence and virulence-associated genes. Discriminatory power of MLVA (as determined by Simpson Index of Discrimination) was higher than the discriminatory power of any of the other three methods. MLVA markers targeted were found to be stable and did not change when three isolates were passaged daily for 70 days. Cluster analyses of MLVA, PFGE and MLST consistently grouped the same isolates into three major clusters, each of which includes one of the three major L. monocytogenes epidemic clones (i.e., ECI, ECIa and ECII). We conclude that the MLVA method described here (i) provides for more discriminatory subtyping of L. monocytogenes serotype 4b strains than the other three methods, (ii) identifies three major groups within the serotype 4b, which are consistent with the groups identified by other subtyping methods. and (iii) is easy to interpret. Use of MLVA may thus be recommended for subtyping of serotype 4b isolates, including as a secondary more discriminatory subtyping method that could be used after initial isolate characterization by PFGE or ribotyping. (C) 2008 Elsevier B.V. All rights reserved.