The Investigation to identify the virulent factors responsible for the severity of secondary pneumococcal pneumonia

2015 Fiscal Year Final Research Report

• Project/Area Number: 26860769
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Infectious disease medicine
• Research Institution: National Institute of Infectious Diseases (2015); Nagasaki University (2014)
• Principal Investigator: NAKAMURA SHIGEKI 国立感染症研究所, その他部局等, 研究員 (20399752)
• Research Collaborator: WEISER Jeffrey ; SUNAZUKA Toshiaki
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 肺炎球菌 / インフルエンザウイルス / 二次性肺炎球菌性肺炎 / マクロライド

Outline of Final Research Achievements

We successfully established the experimental model of post-influenza secondary pneumococcal pneumonia. Next we found the candidate genes responsible for the severity of secondary pneumococcal pneumonia by using deleted mutants. The percent survival was significantly restored in the mice co-infected with influenza and deleted mutants, ΔCbpA, ΔNanA, ΔBgaA, ΔSpxB compared with wild strain. In addition, the excessive production of TNF-α induced by co-infection from the murine peritoneal macrophages was significantly reduced by macrolide antibiotics. Furthermore the percent survival of co-infected mice treated with intraperitoneal administration of 50mg/kg azithromycin for 3 days after pneumococcal co-infection is prone to restore compared with control mice. Taken together of these results, we are able to elucidate the bacterial factors related to the severity of secondary pneumococcal pneumonia and the potency of macrolides to improve the prognosis by its immunomodulately effects.

Free Research Field

呼吸器内科学、感染症学