GntR is involved in the expression of virulence in strain Streptococcus suis P1/7.

ABSTRACT

Streptococcus suis is a severe zoonotic pathogen, responsible for acute diseases in pigs and human. GntR proteins are widely distributed in various bacterial species. In a previous study, GntR proteins were reported to be involved in virulence in many pathogens. To investigate the relationship between GntR and S. suis serotype 2, we constructed an isogenic deletion mutant P1/7ΔgntR and an isogenic single-nucleotide substitution mutant P1/7gntR(SC070731), which took strain P1/7 as parent. The results show that the mutants P1/7ΔgntR and P1/7gntR(SC070731) have a stronger ability to tolerate oxidative stress and to reproduce in blood. Moreover, a higher fatality rate was observed in mice when challenged with P1/7ΔgntR or P1/7gntR(SC070731) compared with that of P1/7. Overall, all results suggest that GntR greatly impacts the virulence of S. suis serotype 2 strain P1/7 and give a new perspective on virulence generation in S. suis.