Burkholderia pseudomallei is a Gram-negative bacterium that causes the sapronotic disease melioidosis. An outbreak in 2003 in the state of Ceara, Brazil, resulted in subsequent surveillance and environmental sampling which led to the recognition of B. pseudomallei as an endemic pathogen in that area. From 2003 to 2015, 24 clinical and 12 environmental isolates were collected across Ceara along with one from the state of Alagoas. Using next-generation sequencing, multilocus sequence typing, and single nucleotide polymorphism analysis, we characterized the genomic diversity of this collection to better understand the population structure of B. pseudomallei associated with Ceara. We found that the isolates in this collection form a distinct subclade compared to other examples from the Western Hemisphere. Substantial genetic diversity among the clinical and environmental isolates was observed, with 14 sequence types (STs) identified among the 37 isolates. Of the 31,594 core single-nucleotide polymorphisms (SNPs) identified, a high proportion (59%) were due to recombination. Because recombination events do not follow a molecular clock, the observation of high occurrence underscores the importance of identifying and removing recombination SNPs prior to evolutionary reconstructions and inferences in public health responses to B. pseudomallei outbreaks. Our results suggest long-term B. pseudomallei prevalence in this recently recognized region of melioidosis endemicity.

中文翻译：

---

巴西塞阿拉州假鼻疽伯克霍尔德菌的基因组多样性

Burkholderia pseudomallei是一种革兰氏阴性细菌，会导致腐生病类鼻疽。2003 年在巴西塞阿拉州爆发的疫情导致随后的监测和环境采样，导致将假鼻疽芽孢杆菌确认为该地区的地方性病原体。从 2003 年到 2015 年，在塞阿拉州收集了 24 个临床分离株和 12 个环境分离株，还有一个来自阿拉戈斯州。使用二代测序、多位点序列分型和单核苷酸多态性分析，我们表征了该集合的基因组多样性，以更好地了解假鼻疽芽孢杆菌的种群结构与塞阿拉有关。我们发现，与来自西半球的其他例子相比，该集合中的分离株形成了一个独特的子分支。观察到临床和环境分离株之间的大量遗传多样性，在 37 个分离株中鉴定出 14 种序列类型 (ST)。在确定的 31,594 个核心单核苷酸多态性 (SNP) 中，很大一部分 (59%) 是由于重组。由于重组事件不遵循分子钟，高发生率的观察强调了在进化重建之前识别和去除重组 SNP 的重要性，以及对假鼻疽芽孢杆菌爆发的公共卫生反应的推断。我们的结果表明长期B.pseudomallei 在这个最近确认的类鼻疽流行地区流行。