The invention discloses an attenuated smooth
Brucella strain and a preparation method and application of a vaccine, the attenuated smooth
Brucella strain is obtained by deleting a bpe275
gene of a
bovine species Brucella A19 strain, the strain is preserved in China General
Microbiological Culture Collection Center (CGMCC) on July 15, 2025, the preservation unit address is CGMCC No.35193, No.1
yard, Beichen West Road, Chaoyang District, Beijing, and the preservation number is CGMCC NO.35193. The classification name of the strain is A19 [
delta] BPE275 bovine
Brucella abortus, a specific fragment of 1431bp can be obtained, the smooth type characteristic is retained, and the sequence of the specific fragment is shown as SEQ ID No.11. The invention also discloses a preparation method of the
Brucella abortus strain. A bpe275
gene deleted strain is constructed by adopting a
Brucella vaccine A19 as a carrier, the survival ability is remarkably reduced, the
toxicity is weakened in a mouse test, and the problem that the
toxicity of a current
Brucella vaccine is enhanced is solved; the smooth characteristic of the parent strain is maintained, the passage is stable, the bacterial form is not changed, and the
organism can be stimulated to generate stronger
cellular immunity.