Burkholderia pseudomallei is an opportunistic soil pathogen that causes melioidosis, a life-threatening human disease prevalent in Southeast Asia, northern Australia, the Middle East, Africa, and South America. The organism also causes disease in plants and animals. Persons with severe melioidosis usually die of septicemia. Relatively little is known regarding the virulence mechanisms of B. pseudomallei; however, several putative virulence determinants have been identified. The organism is able to invade and replicate within phagocytic cells and is particularly pathogenic in males with diabetes mellitus. B. thailandensis is closely related to B. pseudomallei, but is not pathogenic. This study examines various in vitro monocyte / macrophage infection models used to study innate immune responses to B. pseudomallei. Several monocyte and macrophage models showed little or no significant differences between proinflammatory cytokines secreted in response to infection with B. pseudomallei and B. thailandensis. Peripheral blood monocytes from diabetic males produced lower normalized levels of proinflammatory cytokines IL-1α, IL-1β, IL-6, and IL-8 than monocytes from healthy males in response to infection with B. pseudomallei, B. thailandensis, and E. coli. Surprisingly, normalized levels of secreted IL-1β from B. pseudomallei-infected monocytes from diabetic females were higher than levels from healthy females. The results revealed a significant interactive effect of gender and diabetic state on peripheral blood monocyte secretion of IL-1β (p = 0.0370) and IL-8 (p = 0.0390), as well as a significant interactive effect of diabetic state and type of infectious agent on peripheral blood monocyte secretion of IL-1α (p=0.0210) and IL-6 (p=0.0204). These results may help explain why diabetic males are unusually susceptible to infection with B. pseudomallei.



College and Department

Life Sciences; Microbiology and Molecular Biology



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Document Type





Burkholderia pseudomallei, melioidosis, cytokines, inflammation, host-pathogen interactions, diabetes mellitus, Burkholderia thailandensis, immununology



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Microbiology Commons