Unraveling Brucella genomics and pathogenesis in immunocompromised IRF-1-/- mice.
OBJECTIVE
Brucellosis causes abortion in domestic animals and Malta fever in humans. Comparison of Brucella species genomes may reveal potential virulence mechanisms. Engineering bioluminescent Brucella would permit monitoring bacterial dissemination.


METHODS
Microarray of the B. melitensis genome allowed comparison of gene content from six Brucella species. Bioluminescent B. melitensis strains were developed using transposon mutagenesis permitting the study of pathogenic Brucella in mice. Monitoring bacterial dissemination as well as organ localization permits evaluating the role of genes and genomic islands in mutant bacteria.


RESULTS
Comparative genomic analysis revealed 217 ORFs altered in five Brucella species and were often found in islands. Bioluminescent bacteria disseminated from the injection site to liver, spleen, inguinal lymph nodes, testes and submanibular region.


CONCLUSIONS
Genomic islands contribute to Brucella pathogenicity. Biophotonic imaging suggests that Brucella dissemination in mice parallels acute and chronic infections of humans.
Rajashekara
Gireesh
G
Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, 53706, USA.
Krepps
Michael
M
Eskra
Linda
L
Mathison
Angela
A
Montgomery
Alison
A
Ishii
Yohei
Y
Splitter
Gary
G
D000818:Animals; D017347:Brucella melitensis / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D002006:Brucellosis / Q000175:diagnosis / Q000382:microbiology*; D004195:Disease Models, Animal; D018450:Disease Progression; D044404:Genomic Islands / Q000235:genetics* / Q000276:immunology; D016867:Immunocompromised Host; D050856:Interferon Regulatory Factor-1 / Q000172:deficiency* / Q000276:immunology*; D008163:Luminescent Measurements; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D009928:Organ Specificity; D013045:Species Specificity; D014774:Virulence / Q000235:genetics
D050856:Interferon Regulatory Factor-1; C494258:Irf1 protein, mouse; D008164:Luminescent Proteins