Project description:Bordetella bronchiseptica is a gram-negative respiratory pathogen that causes a diverse spectrum of respiratory disease in a wide-range of hosts. We sought to determine if strains of B. bronchiseptica differed in virulence using the mouse model of infection. Mean lethal doses (LD50) of different B. bronchiseptica strains varied widely in the murine model. B. bronchiseptica strain 253 had a LD50 that was 10-fold lower than the prototypical and fully sequenced B. bronchiseptica strain RB50. Using whole genomic transcriptome analysis covering 100% of B. bronchisetpctica strain RB50ÃÂs predicted open reading frames (ORFs), 253 was identified as lacking expression of adenylate cyclase toxin (ACT). Using whole genomic comparative genomic hybridization analysis and whole genome sequencing, we determined that the cya operon, which is required for ACT production, was absent from the 253 genome.
Project description:Bordetella bronchiseptica is a gram-negative respiratory pathogen that causes a diverse spectrum of respiratory disease in a wide-range of hosts. We sought to determine if strains of B. bronchiseptica differed in virulence using the mouse model of infection. Mean lethal doses (LD50) of different B. bronchiseptica strains varied widely in the murine model. B. bronchiseptica strain 253 had a LD50 that was 10-fold lower than the prototypical and fully sequenced B. bronchiseptica strain RB50. Using whole genomic transcriptome analysis covering 100% of B. bronchisetpctica strain RB50ÃÂÃÂs predicted open reading frames (ORFs), 253 was identified as lacking expression of adenylate cyclase toxin (ACT).
Project description:Bordetella bronchiseptica RB50 was shifted from iron replete to either iron depleted or iron replete media, and samples were taken post shift for transcriptional profiling
Project description:The respiratory tract is constantly exposed to the environment and displays a favorable niche for colonizing microorganisms. However, the effects of respiratory bacterial carriage on the immune system and its implications for secondary responses remain largely unclear. We have employed respiratory carriage with Bordetella bronchiseptica (Bb) as the underlying model to comprehensively address effects on subsequent immune responses. Persistent carriage was associated with the stimulation of Bordetella-specific CD4+, CD8+ and CD4+CD25+Foxp3+ T cell responses and broad transcriptional activation was observed in CD4+CD25+ T cells. Importantly, transfer of lymphocytes from persistent carriers to acutely B. bronchiseptica infected mice resulted in a significantly increased bacterial burden in the recipient’s upper respiratory tract. In contrast, we found that B. bronchiseptica carriage resulted in a significant benefit for the host in systemic infection with Listeria monocytogenes. At the same time, vaccination and influenza A virus infection were unaffected. These data demonstrate that there are significant immune modulatory processes triggered by persistent B. bronchiseptica carriage that differentially affect subsequent immune responses. Thereby our results demonstrate the complexity of immune regulation induced by persistent bacterial carriage in the respiratory tract that can be beneficial or detrimental to the host, depending on the pathogen and the considered compartment.
Project description:Comparative genome hybridization (CGH) of sample of 58 Bordetella bronchiseptica, B. pertussis, and B. parapertussis strains selected to span four clusters as defined by MLST.
