About Brucella

General information:
Gram-negative coccobacilli, belong to the α2 subdivision of the proteobacteria, along with ochrobactrum, rhizobium, rhodobacter, agrobacterium, bartonella, and rickettsia.
The genus Brucella consists of six classic species, designated on the basis of host preference, antigenic and biochemical characteristics as Brucella melitensis (goats and sheep), Brucella abortus (cattle), Brucella suis (pigs), Brucella canis (dogs), Brucella ovis (sheep) and Brucella neotomae (wood rats).
Two new brucella species, provisionally called B. pinnipediae and B. cetaceae, have been isolated from marine hosts within the past few years.
Characteristics:
Aerobic facultative intracellular pathogen.
Brucella is unusual in several ways. First, the bacterium does not bear classic virulence factors, such as capsules, secreted proteases, exotoxins, endotoxins, pili and/or fimbriae or virulence plasmids, and its lipopolysaccharide pathogenicity is not typical. Second, it exhibits a tendency to invade and persist in the human host through inhibition of programmed cell death.
Its virulence depends on survival and replication properites in different cell types in which brucella controls the maturation of its vacuole to avoid innate immune responses and to reach its replicative niche associated with the endoplasmic reticulum.
Disease:
Bacteria of the genus Brucella are the causative agents of brucellosis, a worldwide zoonosis that affects a broad range of mammals, including livestock and humans.
Four species of brucella can cause human disease: B. melitensis, B. abortus, B. suis, and B. canis. In humans, brucellosis is a systemic, febrile illness resulting in osteoarthritis, endocarditis and several neurological disorders.
Selected genomes: ⇒ comparative pathogenomics ⇐
B. abortus bv. 1 str. 9-941 chromosome I, 2124241 bp, NC_006932
B. abortus bv. 1 str. 9-941 chromosome II, 1162204 bp, NC_006933
B. abortus S19 chromosome 1, 2122487 bp, NC_010742
B. abortus S19 chromosome 2, 1161449 bp, NC_010740
B. canis ATCC 23365 chromosome I, 2105969 bp, NC_010103
B. canis ATCC 23365 chromosome II, 1206800 bp, NC_010104
B. melitensis ATCC 23457 chromosome I, 2125701 bp, NC_012441
B. melitensis ATCC 23457 chromosome II, 1185518 bp, NC_012442
B. melitensis biovar Abortus 2308 chromosome I, 2121359 bp, NC_007618
B. melitensis biovar Abortus 2308 chromosome II, 1156948 bp, NC_007624
B. melitensis bv. 1 str. 16M chromosome I, 2117144 bp, NC_003317
B. melitensis bv. 1 str. 16M chromosome II, 1177787 bp, NC_003318
B. ovis ATCC 25840 chromosome I, 2111370 bp, NC_009505
B. ovis ATCC 25840 chromosome II, 1164220 bp, NC_009504
B. suis 1330 chromosome I, 2107794 bp, NC_004310
B. suis 1330 chromosome II, 1207381 bp, NC_004311
B. suis ATCC 23445 chromosome I, 1923763 bp, NC_010169
B. suis ATCC 23445 chromosome II, 1400844 bp, NC_010167
Related publications:
DelVecchio VG, et al., 2002. The genome sequence of the facultative intracellular pathogen Brucella melitensis. Proc Natl Acad Sci USA 99(1):443-448.
Paulsen IT, et al., 2002. The Brucella suis genome reveals fundamental similarities between animal and plant pathogens and symbionts. Proc Natl Acad Sci USA 99(20):13148-13153.
Halling SM, et al., 2005. Completion of the genome sequence of Brucella abortus and comparison to the highly similar genomes of Brucella melitensis and Brucella suis. J Bacteriol 187(8):2715-2726.
Chain PS, et al., 2005. Whole-genome analyses of speciation events in pathogenic Brucellae. Infect Immun 73(12):8353-8361.
Crasta OR, et al., 2008. Genome sequence of Brucella abortus vaccine strain S19 compared to virulent strains yields candidate virulence genes. PLoS ONE 3(5):e2193.
Figures:
Nonopsonic entry and subsequent trafficking of Brucella spp. in macrophages (From: Atluri VL, et al., 2011. Interactions of the human pathogenic Brucella species with their hosts. Annu. Rev. Microbiol. 65:523-541.).

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