Detection and phylogenomics of the environmental opportunistic pathogen, Burkholderia pseudomallei, and its close phlyogenetic relatives in the B. pseudomallei complex

Hall, Carina Marie (2021) Detection and phylogenomics of the environmental opportunistic pathogen, Burkholderia pseudomallei, and its close phlyogenetic relatives in the B. pseudomallei complex. Doctoral thesis, Northern Arizona University.

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Abstract

Burkholderia pseudomallei, a Gram-negative environmental bacterium, is the causative agent of the disease melioidosis. Most melioidosis cases are reported from tropical regions in northern Australia and Southeast Asia where B. pseudomallei is endemic in the environment but the true global distribution appears to be much larger. The B. pseudomallei complex (Bpc) is a phylogenetic group of Burkholderia species that consist of B. pseudomallei and its closest phylogenetic relatives. Of the six described species in the Bpc, B. pseudomallei has adapted to opportunistic pathogenicity, B. mallei to obligate pathogenicity, and B. thailandensis, B. oklahomensis, B. humptydooensis, and B. singularis to environmental saprophytism with occasional pathogenicity (except B. humptydooensis).Determining where B. pseudomallei is present in the environment is crucial for understanding the potential risk to humans of acquiring melioidosis since almost all infections with B. pseudomallei are independently acquired from the environment. In Chapter 2, our goal was to gain a better understanding of the prevalence and geographic distribution of B. pseudomallei and other Burkholderia spp. in the environment in Puerto Rico. The results from Chapter 2 suggest that B. pseudomallei is widely dispersed but rare in the environment in Puerto Rico. In Chapter 3, we isolated a member of the Bpc, B. thailandensis, from the Western Hemisphere for the first time. B. thailandensis is of interest from a public health standpoint due to its potential to cause infection as a fortuitous pathogen and to the melioidosis community since B. thailandensis is often used as a surrogate in the laboratory instead of B. pseudomallei due to the reduced restrictions required. In Chapter 4, we proposed two novel Bpc species, B. mayonis sp. nov. and B. savannae sp. nov., isolated from soils from multiple locations in northern Australia. The addition of B. mayonis sp. nov. and B. savannae sp. nov. results in a total of eight species within this significant complex of bacteria that are available for future studies. Understanding the genomics and virulence of B. pseudomallei and its closest relatives in Bpc is important for identifying robust diagnostic targets specific to B. pseudomallei and understanding evolution of virulence in B. pseudomallei.

Item Type:	Thesis (Doctoral)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Burkholderia mayonis; Burkholderia pseudomallei; Burkholderia pseudomallei complex; Burkholderia savannae; Burkholderia thailandensis; melioidosis
Subjects:	R Medicine > RB Pathology
MeSH Subjects:	C Diseases > C01 Bacterial Infections and Mycoses
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > Biological Sciences
Date Deposited:	02 Feb 2022 21:41
Last Modified:	28 Dec 2022 08:30
URI:	https://openknowledge.nau.edu/id/eprint/5635

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