Streptococcus mutans clonal variation revealed by multilocus sequence typing
Streptococcus mutans clonal variation revealed by multilocus sequence typing
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DOI：
10.1128/jcm.02343-06
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发表时间：
2007-08-01
影响因子：
9.4
通讯作者：
Nakagawa, Ichiro
中科院分区：
文献类型：
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作者：
Nakano, Kazuhiko;Lapirattanakul, Jinthana;Nakagawa, Ichiro
变形链球菌是龋病的主要病原菌，是一种依赖生物膜的传染病，偶尔会引起感染性心内膜炎。变形链球菌分为四个血清型(c、e、f和k)。然而，关于变形链球菌的种群，包括变形链球菌菌株之间的克隆关系，以及与引起系统性疾病的特定克隆有关的情况，人们知之甚少。为了解决这个问题，我们开发了一种针对变形链球菌的多位点序列分型(MLST)方案。从日本和芬兰的4种血清型收集的102株变形链球菌中，分别对8个看家基因片段进行了测序。每个座位识别出14到23个等位基因，理论上使我们能够区分1.2×10(10)以上的序列类型。我们在这102株菌株中确定了92种序列类型，表明变形链球菌包含一个多样化的群体。而血清型c型菌株在树状图中广泛分布，而血清型e、f和k型菌株分化为克隆复合体。因此，我们得出结论，变形链球菌的祖先株是c型。没有鉴定出地理特异性。然而，胶原结合蛋白基因(CNM)的分布和母婴传播的直接证据是明显的。综上所述，这种MLST方案对变形链球菌的优越的区分能力可能具有重要的实际意义。
Streptococcus mutans is the major pathogen of dental caries, a biofilm-dependent infectious disease, and occasionally causes infective endocarditis. S. mutans strains have been classified into four serotypes (c, e, f, and k). However, little is known about the S. mutans population, including the clonal relationships among strains of S. mutans, in relation to the particular clones that cause systemic diseases. To address this issue, we have developed a multilocus sequence typing (MLST) scheme for S. mutans. Eight housekeeping gene fragments were sequenced from each of 102 S. mutans isolates collected from the four serotypes in Japan and Finland. Between 14 and 23 alleles per locus were identified, allowing us theoretically to distinguish more than 1.2 x 10(10) sequence types. We identified 92 sequence types in these 102 isolates, indicating that S. mutans contains a diverse population. Whereas serotype c strains were widely distributed in the dendrogram, serotype e,f, and k strains were differentiated into clonal complexes. Therefore, we conclude that the ancestral strain of S. mutans was serotype c. No geographic specificity was identified. However, the distribution of the collagen-binding protein gene (cnm) and direct evidence of mother-to-child transmission were clearly evident. In conclusion, the superior discriminatory capacity of this MLST scheme for S. mutans may have important practical implications.