Environmental and Public Health Microbiology Research Group, School of Veterinary and Biomedical Sciences, James Cook University, Townsville, Australia.
PLoS One. 2011 Mar 31;6(3):e18343. doi: 10.1371/journal.pone.0018343.
The island of New Guinea is located midway between the world's two major melioidosis endemic regions of Australia and Southeast Asia. Previous studies in Papua New Guinea have demonstrated autochthonous melioidosis in Balimo, Western province. In contrast to other regions of endemicity, isolates recovered from both environmental and clinical sources demonstrate narrow genetic diversity over large spatial and temporal scales.
METHODOLOGY/PRINCIPAL FINDINGS: We employed molecular typing techniques to determine the phylogenetic relationships of these isolates to each other and to others worldwide to aid in understanding the origins of the Papua New Guinean isolates. Multi-locus sequence typing of the 39 isolates resolved three unique sequence types. Phylogenetic reconstruction and Structure analysis determined that all isolates were genetically closer to those from Australia than those from Southeast Asia. Gene cluster analysis however, identified a Yersinia-like fimbrial gene cluster predominantly found among Burkholderia pseudomallei derived from Southeast Asia. Higher resolution VNTR typing and phylogenetic reconstruction of the Balimo isolates resolved 24 genotypes with long branch lengths. These findings are congruent with long term persistence in the region and a high level of environmental stability.
CONCLUSIONS/SIGNIFICANCE: Given that anthropogenic influence has been hypothesized as a mechanism for the dispersal of B. pseudomallei, these findings correlate with limited movement of the indigenous people in the region. The palaeogeographical and anthropogenic history of Australasia and the results from this study indicate that New Guinea is an important region for the further study of B. pseudomallei origins and dissemination.
新几内亚岛位于世界两大类鼻疽病流行区——澳大利亚和东南亚之间。巴布亚新几内亚此前的研究表明，西部省的巴利莫存在地方性类鼻疽病。与其他流行地区不同，从环境和临床来源中分离出的菌株在大的时空尺度上表现出狭窄的遗传多样性。
方法/主要发现：我们采用分子分型技术来确定这些分离株彼此之间以及与世界其他地区的亲缘关系，以帮助了解巴布亚新几内亚分离株的起源。39 株分离株的多位点序列分型确定了三个独特的序列类型。系统发育重建和结构分析表明，所有分离株的遗传关系与澳大利亚的分离株比与东南亚的分离株更近。然而，基因簇分析鉴定出一种主要存在于东南亚来源的类鼻疽伯克霍尔德菌中的类似于耶尔森氏菌的纤毛基因簇。对巴利莫分离株的更高分辨率 VNTR 分型和系统发育重建确定了 24 种基因型，其分支长度较长。这些发现与该地区的长期存在和高水平的环境稳定性相一致。
结论/意义：鉴于人为影响被假设为类鼻疽伯克霍尔德菌传播的一种机制，这些发现与该地区土著人民的有限流动相一致。澳大拉西亚的古地理和人为历史以及本研究的结果表明，新几内亚是研究类鼻疽伯克霍尔德菌起源和传播的一个重要地区。
