Neurotropic Threat Characterization ofBurkholderia pseudomalleiStrains

Abstract

Unique virulence factors of certain strains facilitate central nervous system invasion, regardless of infection route.

Increased Neurotropic Threat from Burkholderia pseudomallei Strains with a B. mallei–like Variation in the bimA Motility Gene, Australia

“…Clinical details and the sequence type determined from multilocus sequence typing of the B. pseudomallei strains investigated are noted (Table). Additional details are described elsewhere ( 11 , 12 , 14 , 15 ). These isolates were chosen to represent B. pseudomallei strains previously identified as having bim Bm (n = 7) and bim Bp (n = 8) alleles within the bimA gene ( 10 , 12 ).…”

“…To mimic natural routes of infection, intranasal or subcutaneous routes were used for inoculation by using methods described previously ( 16 ). B. pseudomallei isolates were cultured to logarithmic phase and prepared for inoculations as previously described ( 11 ).…”

“…Virulence of bim Bm (n = 7) and bim Bp (n = 6) isolates were compared in mice as described previously ( 11 ). The 50% infectious dose (ID 50 ) was determined by using a modified version of the Reed and Meunch method ( 17 ).…”

“…Mice that became moribund during the experimental period were euthanized, and bacterial loads were determined in organs and pathology of CNS investigated. Parallel groups of mice were inoculated with MSHR543 ( bim Bm ) (n = 15) and MSHR305 ( bim Bp ) (n = 15) for assessment of bacterial loads within blood, liver, spleen, lung, cervical lymph node , brain, and nasal-associated lymphoid tissue (NALT) at 2 hours, 1 day, and 3 days postinfection (n = 5 mice per time point) by using methods described previously ( 11 ). The detection limit of bacteria in blood and organs was 2 CFU.…”

“…Neurologic melioidosis is a serious, potentially fatal form of B. pseudomallei infection. Recently, we reported that although B. pseudomallei isolates from patients with neurologic melioidosis do not demonstrate selective neurotropism in an experimental model, a distinct subset of B. pseudomallei isolates appeared equipped for rapid dissemination to multiple tissues, including the central nervous system (CNS), after infection ( 11 ). Correlation of virulence genes of B. pseudomallei with clinical presentations of melioidosis identified the bim Bm allele as a risk factor for neurologic melioidosis ( 12 ).…”