Institut de la Francophonie pour la Médecine Tropicale, BP 9519, Vientiane, Lao People's Democratic Republic.
Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic.
Sci Rep. 2017 Jun 8;7(1):3031. doi: 10.1038/s41598-017-02946-z.
Melioidosis, a severe infection with the environmental bacterium Burkholderia pseudomallei, is being recognised increasingly frequently. What determines its uneven distribution within endemic areas is poorly understood. We cultured soil from a rice field in Laos for B. pseudomallei at different depths on 4 occasions over a 13-month period. We also measured physical and chemical parameters in order to identify associated characteristics. Overall, 195 of 653 samples (29.7%) yielded B. pseudomallei. A higher prevalence of B. pseudomallei was found at soil depths greater than the 30 cm currently recommended for B. pseudomallei environmental sampling. B. pseudomallei was associated with a high soil water content and low total nitrogen, carbon and organic matter content. Our results suggested that a sampling grid of 25 five metre square quadrats (i.e. 25 × 25 m) should be sufficient to detect B. pseudomallei at a given location if samples are taken at a soil depth of at least 60 cm. However, culture of B. pseudomallei in environmental samples is difficult and liable to variation. Future studies should both rely on molecular approaches and address the micro-heterogeneity of soil when investigating physico-chemical associations with the presence of B. pseudomallei.
类鼻疽，一种由环境细菌伯克霍尔德菌引起的严重感染，其发病率正在不断增加。在地方性流行地区，其分布不均匀的原因尚不清楚。我们在 13 个月的时间里，分 4 次在老挝的一块稻田的不同深度对土壤进行了伯克霍尔德菌培养。我们还测量了物理和化学参数，以确定相关特征。总的来说，在 653 个样本中，有 195 个（29.7%）样本中含有伯克霍尔德菌。在土壤深度大于目前推荐的用于环境采样的 30cm 时，发现了更高的伯克霍尔德菌患病率。伯克霍尔德菌与高土壤含水量和低总氮、碳和有机质含量有关。我们的研究结果表明，如果在至少 60cm 的土壤深度采集样本，那么在给定地点使用 25 个五米见方的方格（即 25×25m）的采样网格应该足以检测到伯克霍尔德菌。然而，在环境样本中培养伯克霍尔德菌是困难的，容易发生变异。未来的研究应在调查与伯克霍尔德菌存在相关的理化关联时，既依赖分子方法，又要解决土壤的微观异质性问题。
