A-Z Index × Submit A-Z Index × Submit A-Z Index Search Dropdown × Submit Facebook Twitter LinkedIn Syndicate Emerging Infectious Disease journal ISSN: 1080-6059 Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
Melioidosis, caused by Burkholderia pseudomallei , is an emerging disease in the United States and was declared endemic to the Gulf Coast region in 2022. Melioidosis has been sporadically reported in the American continents, the Caribbean, and more recently in Africa. We conducted lethal dose analyses in BALB/c and C57BL/6 mice exposed to small particle aerosols of B. pseudomallei strains from the Western Hemisphere and Africa. Those isolates exhibit a variety of virulence patterns, including rapidly-lethal disease and delayed onset of fatal disease. We found that the isolates we tested grew similarly in culture but displayed major differences in biofilm formation. Our data contribute to the growing knowledge of geographically distinct B. pseudomallei isolates and aid in ensuring that medical countermeasures in development are effective against a diverse collection of bacterial strains.
Burkholderia pseudomallei , a gram-negative facultative intracellular bacterium, causes the disease melioidosis and is critical to both public health and biodefense research communities ( 1 ). Historically, melioidosis is a public health concern in Southeast Asia and northern Australia; however, the global range of melioidosis is much larger than previously described ( 2 – 4 ). Melioidosis is highly underreported in many areas around the world, including India, Africa, the Caribbean, and the Americas ( 5 – 16 ). Underreporting can be attributed to extremely diverse clinical manifestations, scarcity of appropriate diagnostic tools, and a general lack of knowledge of B. pseudomallei by medical staff in endemic regions outside of the historically prevalent areas. However, frequent case reports detailing new clinical examples of melioidosis underscore the importance of this disease throughout the world, particularly in developing nations. B. pseudomallei is also considered an emerging threat in the United States because of several evolving factors: endemicity in the Gulf Coast region and the Caribbean territories of Puerto Rico and US Virgin Islands ( 7 , 11 , 17 ); documented fatal cases resulting from unintentional importation of the bacterium to the United States by an aromatherapy spray produced in India ( 18 ); evidence of locally acquired melioidosis in Texas ( 12 ); and recent infections in Georgia after a severe weather event ( 19 ).
We examined 10 phylogeographically diverse strains of B. pseudomallei from the Western Hemisphere and 3 strains originating from Ghana in Africa. We performed in vitro growth analyses and biofilm assays of those isolates and calculated 50% lethal dose (LD 50 ) estimations in both the BALB/c and C57BL/6 mouse models of inhalational melioidosis. BALB/c mice are considered an acute model (or less resistant to B. pseudomallei ) and are the model of choice for therapeutic medical countermeasure development ( 20 ). In contrast, C57BL/6 mice are considered a more chronic infection model and are the generally accepted model for vaccine development ( 21 – 25 ).
We grew B. pseudomallei strains in either Luria broth with 4% glycerol (LBG) or 4% glycerol/1% tryptone/0.5% NaCl broth to assess in vitro…