The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America.
U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, San Juan, Puerto Rico, United States of America.
PLoS Negl Trop Dis. 2019 Sep 5;13(9):e0007727. doi: 10.1371/journal.pntd.0007727. eCollection 2019 Sep.
Burkholderia pseudomallei is a soil-dwelling bacterium and the causative agent of melioidosis. The global burden and distribution of melioidosis is poorly understood, including in the Caribbean. B. pseudomallei was previously isolated from humans and soil in eastern Puerto Rico but the abundance and distribution of B. pseudomallei in Puerto Rico as a whole has not been thoroughly investigated.
METHODOLOGY/PRINCIPAL FINDINGS: We collected 600 environmental samples (500 soil and 100 water) from 60 sites around Puerto Rico. We identified B. pseudomallei by isolating it via culturing and/or using PCR to detect its DNA within complex DNA extracts. Only three adjacent soil samples from one site were positive for B. pseudomallei with PCR; we obtained 55 isolates from two of these samples. The 55 B. pseudomallei isolates exhibited fine-scale variation in the core genome and contained four novel genomic islands. Phylogenetic analyses grouped Puerto Rico B. pseudomallei isolates into a monophyletic clade containing other Caribbean isolates, which was nested inside a larger clade containing all isolates from Central/South America. Other Burkholderia species were commonly observed in Puerto Rico; we cultured 129 isolates from multiple soil and water samples collected at numerous sites around Puerto Rico, including representatives of B. anthina, B. cenocepacia, B. cepacia, B. contaminans, B. glumae, B. seminalis, B. stagnalis, B. ubonensis, and several unidentified novel Burkholderia spp.
CONCLUSIONS/SIGNIFICANCE: B. pseudomallei was only detected in three soil samples collected at one site in north central Puerto Rico with only two of those samples yielding isolates. All previous human and environmental B. pseudomallei isolates were obtained from eastern Puerto Rico. These findings suggest B. pseudomallei is ecologically established and widely dispersed in the environment in Puerto Rico but rare. Phylogeographic patterns suggest the source of B. pseudomallei populations in Puerto Rico and elsewhere in the Caribbean may have been Central or South America.
伯克霍尔德氏菌是一种土壤细菌，也是类鼻疽病的病原体。类鼻疽病的全球负担和分布情况尚不清楚，包括在加勒比地区。此前曾在波多黎各东部的人类和土壤中分离到假鼻疽伯克霍尔德氏菌，但尚未对整个波多黎各的假鼻疽伯克霍尔德氏菌的丰度和分布进行彻底调查。
方法/主要发现：我们从波多黎各 60 个地点采集了 600 个环境样本（500 个土壤样本和 100 个水样）。我们通过培养和/或使用 PCR 检测复杂 DNA 提取物中的 DNA 来鉴定假鼻疽伯克霍尔德氏菌。只有一个地点的三个相邻土壤样本通过 PCR 检测呈假鼻疽伯克霍尔德氏菌阳性；我们从其中两个样本中获得了 55 个分离株。55 个假鼻疽伯克霍尔德氏菌分离株在核心基因组中表现出细微的变化，并含有四个新的基因组岛。系统发育分析将波多黎各的假鼻疽伯克霍尔德氏菌分离株分为一个单系群，其中包含其他加勒比地区的分离株，这些分离株嵌套在一个包含来自中/南美洲所有分离株的更大分支内。在波多黎各还普遍观察到其他伯克霍尔德氏菌种；我们从波多黎各多个地点采集的多个土壤和水样中培养了 129 个分离株，包括鲍曼不动杆菌、洋葱伯克霍尔德氏菌、洋葱伯克霍尔德氏菌、洋葱伯克霍尔德氏菌、唐菖蒲伯克霍尔德氏菌、稻黄伯克霍尔德氏菌、鞘氨醇伯克霍尔德氏菌、乌邦恩氏伯克霍尔德氏菌和几个未鉴定的新型伯克霍尔德氏菌种。
结论/意义：仅在波多黎各中北部一个地点的三个土壤样本中检测到假鼻疽伯克霍尔德氏菌，其中只有两个样本产生了分离株。以前所有的人类和环境假鼻疽伯克霍尔德氏菌分离株均来自波多黎各东部。这些发现表明，假鼻疽伯克霍尔德氏菌在波多黎各的生态环境中已经建立并广泛分布，但很罕见。系统发育模式表明，波多黎各和加勒比其他地区的假鼻疽伯克霍尔德氏菌种群的来源可能是中美洲或南美洲。
