Genome degradation in Brucella ovis corresponds with narrowing of its host range and tissue tropism.
Brucella ovis is a veterinary pathogen associated with epididymitis in sheep. Despite its genetic similarity to the zoonotic pathogens B. abortus, B. melitensis and B. suis, B. ovis does not cause zoonotic disease. Genomic analysis of the type strain ATCC25840 revealed a high percentage of pseudogenes and increased numbers of transposable elements compared to the zoonotic Brucella species, suggesting that genome degradation has occurred concomitant with narrowing of the host range of B. ovis. The absence of genomic island 2, encoding functions required for lipopolysaccharide biosynthesis, as well as inactivation of genes encoding urease, nutrient uptake and utilization, and outer membrane proteins may be factors contributing to the avirulence of B. ovis for humans. A 26.5 kb region of B. ovis ATCC25840 Chromosome II was absent from all the sequenced human pathogenic Brucella genomes, but was present in all of 17 B. ovis isolates tested and in three B. ceti isolates, suggesting that this DNA region may be of use for differentiating B. ovis from other Brucella spp. This is the first genomic analysis of a non-zoonotic Brucella species. The results suggest that inactivation of genes involved in nutrient acquisition and utilization, cell envelope structure and urease may have played a role in narrowing of the tissue tropism and host range of B. ovis.
Tsolis
Renee M
RM
Medical Microbiology and Immunology, University of California Davis, Davis, California, USA.
Seshadri
Rekha
R
Santos
Renato L
RL
Sangari
Felix J
FJ
Lobo
Juan M García
JM
de Jong
Maarten F
MF
Ren
Qinghu
Q
Myers
Garry
G
Brinkac
Lauren M
LM
Nelson
William C
WC
Deboy
Robert T
RT
Angiuoli
Samuel
S
Khouri
Hoda
H
Dimitrov
George
G
Robinson
Jeffrey R
JR
Mulligan
Stephanie
S
Walker
Richard L
RL
Elzer
Philip E
PE
Hassan
Karl A
KA
Paulsen
Ian T
IT
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D042061:Brucella ovis / Q000235:genetics* / Q000472:pathogenicity; D004251:DNA Transposable Elements; D017353:Gene Deletion; D016680:Genome, Bacterial; D054884:Host-Pathogen Interactions / Q000235:genetics*; D012756:Sheep / Q000382:microbiology
D001426:Bacterial Proteins; D004251:DNA Transposable Elements