Research regarding mechanism of oral colonization of Streptococcus mutans associated with systemic disease development

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K18777
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 57070:Developmental dentistry-related
• Research Institution: Osaka University
• Principal Investigator: Otsugu Masatoshi 大阪大学, 歯学研究科, 助教 (40803086)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: ミュータンスレンサ球菌 / 感染性心内膜炎 / コラーゲン結合タンパク / 定着メカニズム / 予防

Outline of Final Research Achievements

In this study, the mechanism of colonization of CBP-positive Streptococcus mutans, which expresses a collagen-binding protein on the bacterial surface layer, was investigated in terms of oral bacterial colonization during infancy and its association with breastfeeding practices. Saliva samples from 100 pairs of mothers and their children were collected, then collagen-binding gene (cnm, cbm) detection was performed by PCR with DNA extraction. Overall, the mothers showed a higher CBP-positive rate as compared to the children. Notably, the possession rate of CBP-positive strains in the children was significantly higher in those whose mother also possessed a CBP-positive strain as compared to those whose mother had no such strain. Also, children possessing CBP-positive strains had a significantly shorter breastfeeding period as compared to those without CBP-positive results.

Free Research Field

小児歯科

Academic Significance and Societal Importance of the Research Achievements

う蝕病原性細菌のうち菌体表層にコラーゲン結合タンパクを発現しているミュータンスレンサ球菌(CBP陽性株)は、感染性心内膜炎や脳内微小出血などの全身疾患に関与することを明らかにしてきた。一方で、これらの予防法については明確に確立できておらず、CBP陽性株を口腔内に定着させないことが根本的な予防策といえる。本研究により、CBP陽性株の主要な感染源や口腔内の定着に影響を及ぼす因子を明らかにすることができた。本研究成果は、予防法が確立していない全身疾患において、口腔領域から予防法を提唱するための一途となると考えられる。