Genetic Diversity and Microevolution of Burkholderia pseudomallei in the Environment
Genetic Diversity and Microevolution of Burkholderia pseudomallei in the Environment
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DOI：
10.1371/journal.pntd.0000182
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发表时间：
2008-02-01
影响因子：
3.8
通讯作者：
Peacock, Sharon J.
中科院分区：
文献类型：
--
作者：
Chantratita, Narisara;Wuthiekanun, Vanaporn;Peacock, Sharon J.
背景：土壤中的革兰氏阴性病原体类鼻疽伯克霍尔德氏菌是类鼻疽的病因。这种生物在环境中的多样性和人口结构是不明确的defined.Methods和调查结果：我们进行了研究B。在泰国东北部237.5米（2）的废弃土地内，从100个等距点取样的土壤中发现了假鼻疽。B。在77/100个采样点的直接培养中存在假鼻疽。使用脉冲场凝胶电泳（PFGE）和多位点序列分型（MLST）相结合的方法对来自三个独立采样点的200个原代平板菌落进行基因分型。12个PFGE类型和9个序列类型（ST）被确定，其中大多数只存在于一个单一的采样点。两个采样点包含四个ST，第三个点包含三个ST。虽然三个采样点之间的距离很短（分别为7.6，7.9和13.3米），但只有两个ST存在于一个以上的采样点。三个样品中的每一个的特征在于单个B的局部膨胀。假鼻疽克隆（对应于ST 185、163和93）。PFGE和MLST结果的比较表明，两个ST包含可变PFGE带型类型的菌株，即使在一个单一的MLST定义的clon.Conclusions的地理结构：我们讨论了这种极端结构的基因型和基因型频率的微进化动力学和生态学方面的影响，以及如何我们的结果可能会通知未来的采样策略。
Background: The soil dwelling Gram-negative pathogen Burkholderia pseudomallei is the cause of melioidosis. The diversity and population structure of this organism in the environment is poorly defined.Methods and Findings: We undertook a study of B. pseudomallei in soil sampled from 100 equally spaced points within 237.5 m(2) of disused land in northeast Thailand. B. pseudomallei was present on direct culture of 77/100 sampling points. Genotyping of 200 primary plate colonies from three independent sampling points was performed using a combination of pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Twelve PFGE types and nine sequence types (STs) were identified, the majority of which were present at only a single sampling point. Two sampling points contained four STs and the third point contained three STs. Although the distance between the three sampling points was low (7.6, 7.9, and 13.3 meters, respectively), only two STs were present in more than one sampling point. Each of the three samples was characterized by the localized expansion of a single B. pseudomallei clone (corresponding to STs 185, 163, and 93). Comparison of PFGE and MLST results demonstrated that two STs contained strains with variable PFGE banding pattern types, indicating geographic structuring even within a single MLST-defined clone.Conclusions: We discuss the implications of this extreme structuring of genotype and genotypic frequency in terms of micro-evolutionary dynamics and ecology, and how our results may inform future sampling strategies.