Molecular mechanisms of severe invasive group G streptococcal infections

2014 Fiscal Year Final Research Report

• Project/Area Number: 25860330
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Bacteriology (including mycology)
• Research Institution: Research Institute, International Medical Center of Japan
• Principal Investigator: WATANABE Shinya 独立行政法人国立国際医療研究センター, その他部局等, その他 (60614956)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: G群レンサ球菌 / マウス感染モデル / 侵襲性感染症 / 溶血毒素 / ストレプトリジンS

Outline of Final Research Achievements

Recent epidemiological studies reveal that invasive infections caused by Streptococcus dysgalactiae subsp. equisimilis (SDSE), which has Lancefield group G or C antigens, have been increasing in Asia, Europe and the US. The mechanisms and key virulence factors by which SDSE causes invasive diseases are poorly understood. We analyzed the SDSE transcriptome in vivo during intraperitoneal infection in mice using the SDSE specific microarray. The data indicated that SDSE virulence factors were induced during infection. We also created a deletion mutant of csrS encoding a global negative virulence gene regulator and the mutant induced severe systemic hemolysis in mice. The most frequently isolated stG6792 strains secreted abundant SLS and SLO rather than other SDSE emm types. Our findings suggest that these virulence factors might play an important role in invasive diseases induced by SDSE.

Free Research Field

細菌学・感染症学