Environmental & Public Health Microbiology Research Group, School of Veterinary & Biomedical Sciences, James Cook University, Townsville, Australia.
J Clin Microbiol. 2013 Aug;51(8):2520-5. doi: 10.1128/JCM.00418-13. Epub 2013 May 22.
It has been hypothesized that biogeographical boundaries are a feature of Burkholderia pseudomallei ecology, and they impact the epidemiology of melioidosis on a global scale. This study examined the relatedness of B. pseudomallei sourced from islands in the Torres Strait of Northern Australia to determine if the geography of isolated island communities is a determinant of the organisms' dispersal. Environmental sampling on Badu Island in the Near Western Island cluster recovered a single clone. An additional 32 clinical isolates from the region were sourced. Isolates were characterized using multilocus sequence typing and a multiplex PCR targeting the flagellum gene cluster. Gene cluster analysis determined that 69% of the isolates from the region encoded the ancestral Burkholderia thailandensis-like flagellum and chemotaxis gene cluster, a proportion significantly lower than that reported from mainland Australia and consistent with observations of isolates from southern Papua New Guinea. A goodness-of-fit test indicated that there was geographic localization of sequence types throughout the archipelago, with the exception of Thursday Island, the economic and cultural hub of the region. Sequence types common to mainland Australia and Papua New Guinea were identified. These findings demonstrate for the first time an environmental reservoir for B. pseudomallei in the Torres Strait, and multilocus sequence typing suggests that the organism is not randomly distributed throughout this region and that seawater may provide a barrier to dispersal of the organism. Moreover, these findings support an anthropogenic dispersal hypothesis for the spread of B. pseudomallei throughout this region.
有人假设生物地理边界是伯克霍尔德氏菌假单胞菌生态的一个特征，它们会影响到全世界范围内的类鼻疽病的流行病学。本研究检测了澳大利亚北部托雷斯海峡岛屿上分离的伯克霍尔德氏菌假单胞菌之间的亲缘关系，以确定孤立岛屿社区的地理位置是否会影响该生物的传播。在努拉伯勒-伯德群岛的巴杜岛上进行环境采样，仅回收了一个克隆。从该地区另外采集了 32 株临床分离株。通过多位点序列分型和针对鞭毛基因簇的多重 PCR 对分离株进行了特征分析。基因簇分析确定，该地区 69%的分离株编码祖先伯克霍尔德氏菌泰国样鞭毛和趋化性基因簇，这一比例明显低于澳大利亚大陆的报告值，与巴布亚新几内亚南部分离株的观察结果一致。拟合优度检验表明，整个群岛的序列类型存在地理定位，除了该地区的经济和文化中心星期四岛以外。还鉴定出了与澳大利亚大陆和巴布亚新几内亚共有的序列类型。这些发现首次证明了托雷斯海峡存在伯克霍尔德氏菌假单胞菌的环境储库，多位点序列分型表明该生物在该地区并非随机分布，海水可能是该生物传播的障碍。此外，这些发现支持了人为传播假设，即该生物通过该地区传播。
