Abstract and Introduction
Abstract
Burkholderia thailandensis, an opportunistic pathogen found in the environment, is a bacterium closely related to B. pseudomallei, the cause of melioidosis. Human B. thailandensis infections are uncommon. We isolated B. thailandensis from water in Texas and Puerto Rico and soil in Mississippi in the United States, demonstrating a potential public health risk.
Introduction
Burkholderia thailandensis, a gram-negative bacterium found in the environment, poses a public health threat both because of its ability to cause infections as an opportunistic pathogen and potential misidentification as the more pathogenic B. pseudomallei, its closest phylogenetic relative.[1–4]B. pseudomallei, designated a Select Agent by the US Federal Select Agents Program and the causative pathogen of melioidosis, and B. thailandensis are found in the environment in some tropical regions, including Southeast Asia and northern Australia. B. thailandensis, a Biosafety Level 2 organism not classified as a Select Agent,[3] has fewer safety restrictions than B. pseudomallei, and because it can be handled outside of Biosafety Level 3 laboratories, it is used by researchers as a surrogate in some experiments.[5] In laboratory analyses, B. thailandensis is challenging to distinguish from B. pseudomallei because of their similar biochemical phenotypes, the only difference being that B. thailandensis can assimilate L-arabinose.[1,3]B. thailandensis was described after researchers observed reduced virulence in an environmental isolate thought to be B. pseudomallei. Subsequent 16S rRNA gene analysis revealed a novel Burkholderia species named B. thailandensis after the geographic origin of the type strain.[3]
Human B. thailandensis infections are uncommon,[1,4] especially in the Western Hemisphere. Three previous clinical cases in that region have been reported, all from the southern United States: Louisiana in 1997, Texas in 2003,[1] and Arkansas in 2017.[4] Environmental sampling related to the 2003 case in Texas and previous environmental sampling for B. pseudomallei complex members did not recover B. thailandensis.[6]B. thailandensis has been described primarily from the environment in Southeast Asia and Australia[3,7] and, recently, Africa.[8] Occurrence of B. thailandensis in the environment in the Western Hemisphere remains poorly understood. We used a systematic approach to detect and isolate B. thailandensis from soil and water samples collected in Texas in November 2019 and November 2020[9] and Puerto Rico during December 2018–March 2020.
Emerging Infectious Diseases. 2023;29(3):618-621. © 2023 Centers for Disease Control and Prevention (CDC)
