Results 1 -
5 of
5
Course of Infection with the Emergent Pathogen Brucella microti
, 2011
"... A new Brucella species, Brucella microti, has been isolated from wild rodents and found to be pathogenic in mice. The biological relevance of this new mouse pathogen is clear, as it allows us to study Brucella infection in a species-specific model. The course of infection in wild-type (wt) and immun ..."
Abstract
- Add to MetaCart
(Show Context)
A new Brucella species, Brucella microti, has been isolated from wild rodents and found to be pathogenic in mice. The biological relevance of this new mouse pathogen is clear, as it allows us to study Brucella infection in a species-specific model. The course of infection in wild-type (wt) and immunodeficient mice that lack B (Jh), T and B (SCID), or T, B, and NK (SCID.Beige) cells was analyzed over 3 weeks. wt mice completely cleared bacteria from the liver and spleen after that time. However, SCID mice showed a much higher bacterial load in the spleen and liver than wt and Jh mice after 1 week and maintained the same level during the next 2 weeks. All mice tested survived for the 3 weeks. In contrast, the bacterial levels in mice that lacked NK cell activity progressively increased and these mice succumbed to infection after 16 to 18 days. Histopathology analysis of infected mice showed extensive areas of necrotic tissue and thrombosis in liver after 1 week in all infected SCID.Beige mice but were not seen in either SCID or wt animals. These processes were dramatically increased after 21 days, corresponding with the death of SCID.Beige animals. Our results indicate that T and/or B cells are required for the control of infection with the mouse pathogen Brucella microti in liver and spleen but that NK cells are crucial for survival in the absence of B and T cells. In addition, they suggest that controlled granuloma formation is critical to clear this type of infection in wt mice.
Comparative Phylogenomics and Evolution of the Brucellae Reveal a Path to Virulence
"... Brucella species include important zoonotic pathogens that have a substantial impact on both agriculture and human health throughout the world. Brucellae are thought of as “stealth pathogens ” that escape recognition by the host innate immune re-sponse, modulate the acquired immune response, and eva ..."
Abstract
- Add to MetaCart
(Show Context)
Brucella species include important zoonotic pathogens that have a substantial impact on both agriculture and human health throughout the world. Brucellae are thought of as “stealth pathogens ” that escape recognition by the host innate immune re-sponse, modulate the acquired immune response, and evade intracellular destruction. We analyzed the genome sequences of members of the family Brucellaceae to assess its evolutionary history from likely free-living soil-based progenitors into highly successful intracellular pathogens. Phylogenetic analysis split the genus into two groups: recently identified and early-dividing “atypical ” strains and a highly conserved “classical ” core clade containing the major pathogenic species. Lateral gene transfer events brought unique genomic regions into Brucella that differentiated them from Ochrobactrum and allowed the stepwise ac-quisition of virulence factors that include a type IV secretion system, a perosamine-based O antigen, and systems for sequester-ing metal ions that are absent in progenitors. Subsequent radiation within the core Brucella resulted in lineages that appear to have evolved within their preferred mammalian hosts, restricting their virulence to become stealth pathogens capable of causing long-term chronic infections. The Alphaproteobacteria are an ecologically diverse group ofGram-negative bacteria among which several lineages evolved
Review Article
, 2010
"... doi: 10.3389/fmicb.2010.00118 The dawning era of comprehensive transcriptome analysis in ..."
Abstract
- Add to MetaCart
(Show Context)
doi: 10.3389/fmicb.2010.00118 The dawning era of comprehensive transcriptome analysis in
Comparative Genomics of Early-Diverging Brucella Strains Reveals a Novel Lipopolysaccharide Biosynthesis Pathway
"... ABSTRACT Brucella species are Gram-negative bacteria that infect mammals. Recently, two unusual strains (Brucella inopinata BO1T and B. inopinata-like BO2) have been isolated from human patients, and their similarity to some atypical brucellae iso-lated from Australian native rodent species was note ..."
Abstract
- Add to MetaCart
(Show Context)
ABSTRACT Brucella species are Gram-negative bacteria that infect mammals. Recently, two unusual strains (Brucella inopinata BO1T and B. inopinata-like BO2) have been isolated from human patients, and their similarity to some atypical brucellae iso-lated from Australian native rodent species was noted. Here we present a phylogenomic analysis of the draft genome sequences of BO1T and BO2 and of the Australian rodent strains 83-13 and NF2653 that shows that they form two groups well separated from the other sequenced Brucella spp. Several important differences were noted. Both BO1T and BO2 did not agglutinate signif-icantly when live or inactivated cells were exposed to monospecific A andM antisera against O-side chain sugars composed of N-formyl-perosamine. While BO1Tmaintained the genes required to synthesize a typical BrucellaO-antigen, BO2 lackedmany
