Streptococcus suis infection induces to bacterial accumulation in the kidney

Although a Streptococcus suis infection was recently expanded, the study of S. suis has not had enough attention. In this study, bacterial kinetics of S. suis were investigated for seven days of infection in a mouse model. Survival rates showed that 5.0 × 107 CFU ml−1 of S. suis infection caused death in 30% of mice subjects. Streptococcal kinetics from 104 to 107 CFU ml−1 were detected in the brain, kidney, lung, spleen and urine two days post-infection and still detected in both kidney and urine seven days post-infection. In addition, 5.0 × 106 CFU ml−1 of low dose infection was conducted, showing that S. suis was detected in the kidney seven days post-infection. Expressions of virulence-associated genes (mrp, epf, sly and hyl) were evaluated and results showed that all virulence-associated genes were detected in both spleen and kidney, whereas no detectable bands in either lung and liver two days post-infection. Microscopy demonstrated that S. suis accumulated in the renal cortex side of blood vessels and renal tubules two days post-infection, while S. suis accumulated in the renal tubule seven days post-infection. This is the first report of accumulated S. suis in mice kidney during S. suis infection.