A BALB/c mouse model of Streptococcus suis 2 infection

Objective Experiments were conducted to establish a mouse model of infection with Streptococcus suis type 2(SS2).Methods BALB/c mice were infected with 1 ml(2×108 CFU) of SS2 from Sichuan Province via intraperitoneal injection.Mice were observed daily for 7 days to check for clinical manifestations.Results Mice were susceptible to SS2 and displayed clinical symptoms and pathological changes.LD50 was 4×107 CFU/ml.There were significant differences in the distribution of the wild strain and avirulent strain △cps2B in blood and organs.Histopathology indicated that the organs and tissue had typical pathological changes.Wild strains stimulated the secretion of the cytokines MCP-1 and IL-6.Conclusion Results showed that BALB/c mice can provide a good model for studying the pathological mechanism of infection with Streptococcus suis serotype 2.