Attenuation of a Brucella abortus mutant lacking a major 25 kDa outer membrane protein in cattle.
Am J Vet Res
; 62(9): 1461-6, 2001 Sep.
Article
em En
| MEDLINE
| ID: mdl-11560278
ABSTRACT
OBJECTIVE:
To determine the virulence of a Brucella abortus mutant, BA25, lacking a major 25 kd outer membrane protein (Omp25) in cattle. ANIMALS 20 mixed-breed heifers in late gestation. PROCEDURE 10 heifers were inoculated with 1 x 10(7) colony-forming units of the Omp25 mutant via the conjunctival sac, and an equal number were infected with the virulent parental strain B. abortus 2308. The delivery status of the dams was recorded, and colonization was assessed following necropsy. The ability of BA25 to replicate inside bovine phagocytes and chorionic trophoblasts was also evaluated in vitro because of the propensity of virulent brucellae to replicate inside these cells in vivo.RESULTS:
The parental strain induced abortions in 5 of 10 inoculated cattle, whereas only 1 of 10 dams exposed to BA25 aborted. Brucella abortus strain 2308 colonized all of the cow-calf pairs and induced Brucella-specific antibodies in 100% of the dams. In contrast, BA25 was isolated by bacteriologic cultural technique from 30% of the calves and 50% of the inoculated dams (n = 10). Of the 10 heifers inoculated with BA25, 4 did not develop Brucella-specific antibodies nor were they colonized by the mutant strain. In bovine macrophages and chorionic trophoblasts, BA25 replicated in significantly lower numbers than the virulent parental strain (n = 3). CONCLUSIONS AND CLINICAL RELEVANCE The 25 kd outer membrane protein may be an important virulence factor for B. abortus in cattle. The attenuation of the Omp25 mutant in cattle may involve the inability of BA25 to replicate efficiently in bovine phagocytes and chorionic trophoblasts.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Contexto em Saúde:
3_ND
Problema de saúde:
3_neglected_diseases
/
3_zoonosis
Assunto principal:
Proteínas da Membrana Bacteriana Externa
/
Brucella abortus
/
Brucelose Bovina
Limite:
Animals
/
Pregnancy
Idioma:
En
Revista:
Am J Vet Res
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Estados Unidos