Nonrandom distribution of Burkholderia pseudomallei clones in relation to geographical location and virulence
Nonrandom distribution of Burkholderia pseudomallei clones in relation to geographical location and virulence
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DOI：
10.1128/jcm.00629-06
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发表时间：
2006-07-01
影响因子：
9.4
通讯作者：
Peacock, Sharon J.
中科院分区：
文献类型：
--
作者：
Vesaratchavest, Mongkol;Tumapa, Sarinna;Peacock, Sharon J.
假鼻疽伯克霍尔德氏菌是一种生活在土壤中的腐生植物，是类鼻疽病的病原体，类鼻疽病是一种威胁生命的人类感染。大多数病例报告来自泰国东北部和澳大利亚北部。利用多位点序列分型(MLST)，我们比较了(I)泰国东北部土壤和入侵分离物以及(Ii)泰国和澳大利亚入侵分离物。共鉴定了266株泰国假鼻疽杆菌(83株土壤分离株和183株侵袭性分离株)。这些序列类型对应123种序列类型，其中最丰富的是ST70(n=21)、ST167(n=15)、ST54(n=12)。ST58(n=11)。鉴定了两簇相关的克隆复合体(STS)；较大的克隆复合体(CC48)不符合假设祖先的简单径向扩张模式，而第二簇(CC70)对应于ST70的简单径向扩张。尽管有大量的STS，但总的核苷酸多样性很低。在泰国分离株中，在10个最大的克隆中，那些孤立的前线类鼻炎患者的比例过高(P<；0.0001)。环境菌株和病原菌的分类指数有显著差异(P<；0.001)，证实了两个样品之间的基因分布不是随机的。来自澳大利亚的158个分离物(主要是与疾病相关的)的MLST图谱包含许多与泰国侵袭性分离物相似的STS(96)，但在两个群体中都没有发现ST。两个群体的多样性和等位基因频率分布也存在差异。这一分析表明，在地理隔离的基础上存在着强烈的遗传分化，在毒力潜力的基础上存在着显著的分化。
Burkholderia pseudomallei is a soil-dwelling saprophyte and the causative agent of melioidosis, a life-threatening human infection. Most cases are reported from northeast Thailand and northern Australia. Using multilocus sequence typing (MLST), we have compared (i) soil and invasive isolates front northeast Thailand and (ii) invasive isolates front Thailand and Australia. A total of 266 Thai B. pseudomallei isolates were characterized (83 soil and 183 invasive). These corresponded to 123 sequence types (STs), the most abundant being ST70 (n = 21), ST167 (n = 15), ST54 (n = 12). and ST58 (n = 11). Two clusters of related STs (clonal complexes) were identified; the larger clonal complex (CC48) did not conform to a simple pattern of radial expansion from an assumed ancestor, while a second (CC70) corresponded to a simple radial expansion from ST70. Despite the large number of STs, overall nucleotide diversity was low. Of the Thai isolates, those isolated front patients with melioidosis were overrepresented in the 10 largest clones (P < 0.0001). There was a significant difference in the classification index between environmental and disease isolates (P < 0.001), confirming that genotypes were not distributed randomly between the two samples. MLST profiles for 158 isolates from Australia (mainly disease associated) contained a number of STs (96) similar to that seen with the Thai invasive isolates, but no ST was found in both populations. There were also differences in diversity and allele frequency distribution between the two populations. This analysis reveals strong, genetic differentiation on the basis of geographical isolation and a significant differentiation on the basis of virulence potential.