Abstract:
Background: We have previously shown that PCR following enrichment culture is the most sensitive method to detect Burkholderia pseudomallei in environmental samples. Here we report an evaluation of the published consensus method for the culture of B. pseudomallei from Lao soil in comparison with our conventional culture method and with PCR with or without prior broth enrichment. Methods: One hundred soil samples were collected from a field known to contain B. pseudomallei and processed by: (i) the conventional method, (ii-iii) the consensus method using media prepared in either Laos or Thailand, and (iv) the consensus method performed in Thailand, as well as by (v) PCR following direct extraction of DNA from soil and (vi) PCR following broth pre-enrichment. Results: The numbers of samples in which B. pseudomallei was detected were 42, 10, 7, 6, 6 and 84, respectively. However, two samples were positive by the consensus method but negative by conventional culture, and one sample was negative by PCR following enrichment although B. pseudomallei was isolated by the conventional culture method. Conclusions/Discussion: The results show that no single method will detect all environmental samples that contain B. pseudomallei. People conducting environmental surveys for this organism should be aware of the possibility of false-negative results using the consensus culture method. An approach that entails screening using PCR after enrichment, followed by the evaluation of a range of different culture methods on PCR-positive samples to determine which works best in each setting, is recommended.
摘要:
背景:我们先前已经表明,富集培养后的PCR是检测环境样品中假伯克霍尔德菌的最灵敏方法。在这里,我们报告了与我们的常规培养方法以及在有或没有事先进行肉汤富集的情况下进行PCR相比,已发表的来自老挝土壤的假单胞菌培养的共识方法的评估。方法:从已知含有假孢子的田地中收集了一百个土壤样品,并通过以下方法进行处理:(i)常规方法,(ii-iii)使用老挝或泰国准备的媒体的共识方法,和(Iv)在泰国执行的共识方法,以及通过(v)直接从土壤中提取DNA后的PCR和(vi)肉汤预富集后的PCR。结果:检测到假单胞菌的样本数量分别为42、10、7、6、6和84。然而,两个样本通过共识方法为阳性,但通过常规培养为阴性,尽管通过常规培养方法分离了假单胞菌,但富集后的PCR结果为阴性。结论/讨论:结果显示,没有单一方法能够检测到含有假单胞菌的所有环境样品。对这种生物进行环境调查的人们应该意识到使用共识培养方法出现假阴性结果的可能性。一种需要在富集后使用PCR进行筛选的方法,然后对PCR阳性样品进行一系列不同的培养方法的评估,以确定哪种方法在每种情况下效果最好。是推荐的。