[Construction and characterization of Salmonella Pathogenicity Island 2 (SPI-2) deletion mutant of Salmonella Pullorum S06004].

ABSTRACT

OBJECTIVE: To research the pathogenicity of Salmonella Pathogenicity Island 2 (SPI-2) deletion mutant of Salmonella Pullorum and preliminary explore the feasibility of developing safe attenuated Salmonella Pullorum candidate vaccine strain. METHODS: The SPI-2 (-40 kb) deletion mutant of Salmonella Pullorum S06004 was constructed using the λ-red recombinant system. Then the biological characteristics such as growth rate, biochemical properties, genetic stability and virulence were evaluated between the deletion mutant strain S06004ΔSPI2 and its parent strain S06004. RESULTS: S06004ΔSPI2 was successfully constructed. The growth rate and biochemical properties of S06004ΔSPI2 were consistent with those of its parent strain S06004. The mutant was stable with the deletion of SPI-2. Chicken lethal test showed that the LD50 of S06004ΔSPI2 was 252 times higher than the parent strain S06004. CONCLUSION: The virulence of S06004ΔSPI2 was obviously attenuated. This study provided basic data for further study of the functions of SPI-2, and implied its potential to develop attenuated Salmonella vaccine.