Multi-locus sequence typing of Ehrlichia ruminantium strains from geographically diverse origins and collected in Amblyomma variegatum from Uganda.
Multi-locus sequence typing of Ehrlichia ruminantium strains from geographically diverse origins and collected in Amblyomma variegatum from Uganda.
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DOI：
10.1186/1756-3305-4-137
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发表时间：
2011-07-15
影响因子：
3.2
通讯作者：
Sugimoto C
中科院分区：
文献类型：
--
作者：
Nakao R;Magona JW;Zhou L;Jongejan F;Sugimoto C
反刍埃利希体立克次体是反刍动物心脏水的病原体。然而，为了开发新的诊断工具、治疗方法和预防策略，需要更好地了解其不同菌株的群体遗传学。具体而言，制定有效的疫苗接种政策依赖于对田间分离株进行适当的基因分型和特征描述。虽然最近发展了多位点序列分型（MLST），但迄今为止只分析了地理上受限制的菌株。因此，必须扩大MLST数据库以包括具有不同地理起源的全球菌株。在这项研究中，我们使用了一组来自不同地理来源的参考菌株，以及在乌干达心水流行区从其载体变异钝瘤（Amblyomma variegatum）中检测到的反刍大肠杆菌现场样本。共鉴定出31个新的等位基因（分别为gltA、groEL、lepA、lipA、lipB、secY、sodB和sucA位点的6个、4个、6个、3个、2个、5个、3个和2个）和19个新的序列类型。邻结点分析和最小生成树分析表明，这些菌株之间存在高度的遗传异质性。除了来自西非国家的4个STs外，未观察到基因型与地理起源之间的关联。当我们对串联序列进行6种不同的重组测试（GeneConv、Bootscan、MaxChi、Chimaera、SiScan和3Seq）时，在6个不同的STs中确定了4种可能的重组事件。所有的重组断点都位于基因边界附近，表明存在基因间重组。在聚类分析中，所有定位于不同类群的4个STs都显示出相同的重组事件，表明重组可能在e.r uminantium的多样化中发挥重要作用。汇编整个非洲大陆的MLST数据集对于了解非洲国家田间分离株的现有遗传多样性将特别有价值。有关菌株之间交叉保护程度的全面信息，以及对基因型和表型（如疫苗效力）之间可能关系的进一步了解，预计将导致制定区域特异性疫苗接种策略。
The rickettsial bacterium Ehrlichia ruminantium is the causative agent of heartwater in ruminants. A better understanding of the population genetics of its different strains is, however, needed for the development of novel diagnostic tools, therapeutics and prevention strategies. Specifically, the development of effective vaccination policies relies on the proper genotyping and characterisation of field isolates. Although multi-locus sequence typing (MLST) has been recently developed, only strains from geographically restricted collections have been analysed so far. The expansion of the MLST database to include global strains with different geographic origins is therefore essential. In this study, we used a panel of reference strains from geographically diverse origins and field samples of E. ruminantium detected from its vector, Amblyomma variegatum, in heartwater-endemic areas in Uganda. A total of 31 novel alleles (six, four, six, three, two, five, three, and two for gltA, groEL, lepA, lipA, lipB, secY, sodB, and sucA loci, respectively) and 19 novel sequence types (STs) were identified. Both neighbour-joining and minimum spanning tree analyses indicated a high degree of genetic heterogeneity among these strains. No association was observed between genotypes and geographic origins, except for four STs from West African countries. When we performed six different tests for recombination (GeneConv, Bootscan, MaxChi, Chimaera, SiScan, and 3Seq) on concatenated sequences, four possible recombination events were identified in six different STs. All the recombination breakpoints were located near gene borders, indicating the occurrence of intergenic recombination. All four STs that localized to a distinct group in clustering analysis showed evidence of identical recombination events, suggesting that recombination may play a significant role in the diversification of E. ruminantium. The compilation of MLST data set across the African continent will be particularly valuable for the understanding of the existing genetic diversity of field isolates in African countries. Comprehensive information on the degree of cross-protection between strains and further understanding of possible relationships between genotypes and phenotypes such as vaccine efficacy are expected to lead to the development of region-specific vaccination strategies.
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DOI：
10.1196/annals.1355.060
发表时间：
2005-01-01
期刊：
RICKETTSIOSES: FROM GENOME TO PROTEOME, PATHOBIOLOGY, AND RICKETTSIAE AS AN INTERNATIONAL THREAT
影响因子：
--
作者：
Allsopp, MTEP;Louw, M;Meyer, EC
通讯作者：
Meyer, EC
影响因子：
3.7
作者：
Padidam, M;Sawyer, S;Fauquet, CM
通讯作者：
Fauquet, CM
影响因子：
10.7
作者：
Bryant, D;Moulton, V
通讯作者：
Moulton, V
影响因子：
4.2
作者：
Nakao, Ryo;Stromdahl, Ellen Y.;Sugimoto, Chihiro
通讯作者：
Sugimoto, Chihiro
影响因子：
3.3
作者：
Faburay, Bonto;Jongejan, Frans;Geysen, Dirk
通讯作者：
Geysen, Dirk