The comparative study on the LD50 to evaluate the virulence of Vibrio parahaemolyticus using two calculation methods

Abstract:

The Vibrio parahaemolyticus(Vp) is paid much attention to as a zoonosis pathogen at present.In order to compare the virulence and pathogenicity of seven Vp strains from different sources, we used zebrafish as the model to test median lethal dosage (LD₅₀)by acute toxicity experiment within 96h, and analyzed the data with ReeD-Muench method and Bliss method.The results suggested that the LD₅₀ tested by ReeD-Muench method of human pathogenic bacteria (ATCC17802, ATCC33847) and aquatic animal pathogens(Vp13, Vp31, Vp41, Vp57)were 6.0×10⁷, 7.4×10⁷, 3.9×10⁷, 1.6×10⁸, 1.6×10⁸, 9.3×10⁷CFU/mL, respectively and 5.0×10⁷,7.6×10⁷,3.6×10⁷,1.5×10⁸,1.6×10⁸,9.4×10⁷ CFU/mL, respectively, with Bliss method. The results showed that these two kinds of calculation methods had little difference for the LD₅₀, and the virulence of these seven different Vp strains were as follows: Vp13 > ATCC17802 > ATCC33847 > Vp57 > Vp31 > Vp41 > VpKNH1.To conclude, ReeD-Muench method and Bliss method can both be used to test Vp strains virulence.However, Bliss calculation method is more simple and accurate than the ReeD-Muench method with the development of computer technology.As a result, it is the better choice for LD₅₀.