Control mixed infections by suppressing the virulence of multiple bacteria

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K10270
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 57080:Social dentistry-related
• Research Institution: Nagasaki University
• Principal Investigator: NISHIGUCHI MIYUKI 長崎大学, 医歯薬学総合研究科(歯学系), 助教 (10253676)
• Co-Investigator(Kenkyū-buntansha): 鵜飼 孝 長崎大学, 病院(歯学系), 教授 (20295091) ; 近藤 好夫 長崎大学, 医歯薬学総合研究科(歯学系), 准教授 (30581954)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 誤嚥性肺炎 / 口腔常在細菌

Outline of Final Research Achievements

We analyzed Prevotella melaninogenica, an oral commensal organism associated with aspiration pneumonia and found in newborns and the elderly. Prevotella melaninogenica is frequently isolated from specimens with oral infections and is also a causative agent of gynecological infections. Pathogenic factor secretion apparatus mutants showed markedly reduced erythrocyte aggregation ability and virulence in animal studies. We attempted to construct a mouse model of periodontal infection using this bacterium. The method of inoculation of periodontal bacteria into the oral cavity of mice, the amount of inoculum, and the number of inoculations were investigated. After inoculation with periodontal disease bacteria, maxillae of infected and uninfected groups were excised, thin sections were prepared, and HE staining and immunostaining for inflammatory cytokines were performed.

Free Research Field

小児歯科学

Academic Significance and Societal Importance of the Research Achievements

歯周病は糖尿病など全身疾患の重症性に関わる重大な口腔疾病である。本課題においては、歯周病感染マウスモデルの構築を行った。今後の研究において、この動物モデルを用いて、共同研究者が混合感染症における病態を観察し、どの菌の組み合わせが生体にとって組織炎症が起こりやすいのか検証する。また、本課題において静菌候補分子を得ることができており、今後この動物感染モデルを用いて、病原性抑制の可能性を検討し、歯周病や粘膜障害軽減等、臨床での応用を模索する。本研究成果は今後の歯周病に対する予防治療の確立に大いに貢献出来る成果であったと考えられる。