Price Erin P, Sarovich Derek S, Smith Emma J, MacHunter Barbara, Harrington Glenda, Theobald Vanessa, Hall Carina M, Hornstra Heidie M, McRobb Evan, Podin Yuwana, Mayo Mark, Sahl Jason W, Wagner David M, Keim Paul, Kaestli Mirjam, Currie Bart J
Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia.
Appl Environ Microbiol. 2015 Nov 25;82(3):954-63. doi: 10.1128/AEM.03013-15. Print 2016 Feb 1.
Melioidosis is a disease of humans and animals that is caused by the saprophytic bacterium Burkholderia pseudomallei. Once thought to be confined to certain locations, the known presence of B. pseudomallei is expanding as more regions of endemicity are uncovered. There is no vaccine for melioidosis, and even with antibiotic administration, the mortality rate is as high as 40% in some regions that are endemic for the infection. Despite high levels of recombination, phylogenetic reconstruction of B. pseudomallei populations using whole-genome sequencing (WGS) has revealed surprisingly robust biogeographic separation between isolates from Australia and Asia. To date, there have been no confirmed autochthonous melioidosis cases in Australia caused by an Asian isolate; likewise, no autochthonous cases in Asia have been identified as Australian in origin. Here, we used comparative genomic analysis of 455 B. pseudomallei genomes to confirm the unprecedented presence of an Asian clone, sequence type 562 (ST-562), in Darwin, northern Australia. First observed in Darwin in 2005, the incidence of melioidosis cases attributable to ST-562 infection has steadily risen, and it is now a common strain in Darwin. Intriguingly, the Australian ST-562 appears to be geographically restricted to a single locale and is genetically less diverse than other common STs from this region, indicating a recent introduction of this clone into northern Australia. Detailed genomic and epidemiological investigations of new clinical and environmental B. pseudomallei isolates in the Darwin region and ST-562 isolates from Asia will be critical for understanding the origin, distribution, and dissemination of this emerging clone in northern Australia.
类鼻疽病是一种人和动物都会感染的疾病,由腐生菌伯克霍尔德菌引起。曾经认为该病局限于某些特定地区,但随着更多的地方性流行区域被发现,伯克霍尔德菌的已知存在范围正在扩大。目前尚无针对类鼻疽病的疫苗,即使使用抗生素治疗,在某些该感染的地方性流行区域,死亡率仍高达40%。尽管伯克霍尔德菌有高水平的重组现象,但利用全基因组测序(WGS)对伯克霍尔德菌群体进行系统发育重建,却揭示了来自澳大利亚和亚洲的分离株之间惊人的强大生物地理隔离。迄今为止,在澳大利亚尚未有由亚洲分离株引起的确诊本土类鼻疽病病例;同样,在亚洲也未发现起源于澳大利亚的本土病例。在此,我们通过对455个伯克霍尔德菌基因组进行比较基因组分析,证实了在澳大利亚北部达尔文地区前所未有的出现了一种亚洲克隆株,序列类型562(ST-562)。该克隆株于2005年首次在达尔文被发现,由ST-562感染引起的类鼻疽病病例发病率稳步上升,现在已成为达尔文地区的常见菌株。有趣的是,澳大利亚的ST-562似乎在地理上局限于一个单一地点,并且在基因上比该地区其他常见的序列类型多样性更低,这表明该克隆株是最近才被引入澳大利亚北部的。对达尔文地区新的临床和环境伯克霍尔德菌分离株以及来自亚洲的ST-562分离株进行详细的基因组和流行病学调查,对于了解这种新兴克隆株在澳大利亚北部的起源、分布和传播至关重要。