Kaestli Mirjam, Mayo Mark, Harrington Glenda, Watt Felicity, Hill Jason, Gal Daniel, Currie Bart J
Tropical and Emerging Infectious Diseases Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, Northern Territory 0811, Australia.
Appl Environ Microbiol. 2007 Nov;73(21):6891-7. doi: 10.1128/AEM.01038-07. Epub 2007 Sep 14.
Burkholderia pseudomallei, the cause of the severe disease melioidosis in humans and animals, is a gram-negative saprophyte living in soil and water of areas of endemicity such as tropical northern Australia and Southeast Asia. Infection occurs mainly by contact with wet contaminated soil. The environmental distribution of B. pseudomallei in northern Australia is still unclear. We developed and evaluated a direct soil B. pseudomallei DNA detection method based on the recently published real-time PCR targeting the B. pseudomallei type III secretion system. The method was evaluated by inoculating different soil types with B. pseudomallei dilution series and by comparing B. pseudomallei detection rate with culture-based detection rate for 104 randomly collected soil samples from the Darwin rural area in northern Australia. We found that direct soil B. pseudomallei DNA detection not only was substantially faster than culture but also proved to be more sensitive with no evident false-positive results. This assay provides a new tool to detect B. pseudomallei in soil samples in a fast and highly sensitive and specific manner and is applicable for large-scale B. pseudomallei environmental screening studies or in outbreak situations. Furthermore, analysis of the 104 collected soil samples revealed a significant association between B. pseudomallei-positive sites and the presence of animals at these locations and also with moist, reddish brown-to-reddish gray soils.
类鼻疽伯克霍尔德菌是人和动物严重类鼻疽病的病原体,是一种革兰氏阴性腐生菌,存在于澳大利亚北部热带地区和东南亚等流行地区的土壤和水中。感染主要通过接触受污染的潮湿土壤发生。类鼻疽伯克霍尔德菌在澳大利亚北部的环境分布仍不清楚。我们基于最近发表的针对类鼻疽伯克霍尔德菌III型分泌系统的实时PCR技术,开发并评估了一种直接检测土壤中类鼻疽伯克霍尔德菌DNA的方法。通过用类鼻疽伯克霍尔德菌稀释系列接种不同土壤类型,并将104份从澳大利亚北部达尔文农村地区随机采集的土壤样本的类鼻疽伯克霍尔德菌检测率与基于培养的检测率进行比较,对该方法进行了评估。我们发现,直接检测土壤中类鼻疽伯克霍尔德菌DNA不仅比培养法快得多,而且灵敏度更高,没有明显的假阳性结果。该检测方法提供了一种新工具,能够以快速、高度灵敏和特异的方式检测土壤样本中的类鼻疽伯克霍尔德菌,适用于大规模的类鼻疽伯克霍尔德菌环境筛查研究或疫情爆发情况。此外,对104份采集的土壤样本的分析表明,类鼻疽伯克霍尔德菌阳性位点与这些地点动物的存在以及潮湿的红棕色至红灰色土壤之间存在显著关联。