Molecular epidemiological analysis of Streptococcus pneumoniae in middle ear fluid isolates on acute otitis media in children after thirteen-valent pneumococcal conjugate vaccine introduction

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K16885
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Otorhinolaryngology
• Research Institution: Tohoku University
• Principal Investigator: OZAWA DAIKI 東北大学, 医学系研究科, 非常勤講師 (80792267)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 急性中耳炎 / 肺炎球菌 / 血清型 / 薬剤感受性 / 13価肺炎球菌ワクチン

Outline of Final Research Achievements

We surveyed the serotypes and antimicrobial susceptibility profile of 44 S. pneumoniae isolates obtained from the middle ear fluid of children with acute otitis media from March 2017 to February 2018, in order to research serotype replacement after the 13-valent pneumococcal conjugate vaccine (PCV13) introduction in Japan.
The most prevalent serotypes found were serotype 15A (15.9%), and serotype 23B (11.4%). 7-valent pneumococcal conjugate vaccine (PCV7) types accounted for 0% of all strains, while 9.1% were PCV13 types. Serotype 15A strains were 100% non-susceptible to penicillin G.
Finally, the high prevalence of non-susceptible serotype 15A highlights the serotype 15A should be noted as a cause of intractable acute otitis media in children.

Free Research Field

耳鼻咽喉科学

Academic Significance and Societal Importance of the Research Achievements

肺炎球菌は急性中耳炎の代表的な原因菌である。13価結合型肺炎球菌ワクチン (PCV13) は導入後にPCV13が効果を示さない血清型の肺炎球菌が増加する菌交代現象が問題となる。本研究によりPCV13では効果がなく、なおかつペニシリン非感性の血清型15Aが増加していることがわかり、今後の小児急性中耳炎の難治化の原因になる可能性が示唆された。