Systematic re-estimation of polymorphism of T. pallidum genome from wider range of specimens including T. p DNA of lower copy numbers

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K09184
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 56030:Urology-related
• Research Institution: National Institute of Infectious Diseases
• Principal Investigator: Nakayama Shu-ichi 国立感染症研究所, 細菌第一部, 主任研究官 (80280767)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 近縁株を細分化できる１塩基置換候補 / 詳細な菌株系統解析 / MSMとheterosexuals

Outline of Final Research Achievements

Among the T.pallidum strains detected in Japan during 2017, the macrolide resistant strain type 14d/f was found in significantly more cases of syphilis among heterosexuals than in those among men who have sex with men (MSM); i.e., 79% (31/39) of the strains from heterosexuals were 14d/f compared to 37% (7/19) of those from MSM. In addition, 83% (50/60) of the strains were identified as macrolide resistant. 90% (35/39) of the strains from heterosexuals were macrolide resistant compared to 58% (11/19) of those from MSM.
The whole genome sequencing analyses using the strains detected between 2014 and 2018 in Japan showed that these strains were closely related to reported strains in China. However, those strains in these countries evolved independently after diverging from their most recent common ancestor. The genetic difference between the strains in these countries was characterized by single-nucleotide-polymorphism analyses of their penicillin binding protein genes.

Free Research Field

細菌遺伝学

Academic Significance and Societal Importance of the Research Achievements

性感染症の制御においては、科学的根拠に立脚したリスクグループごとへの介入がとくに重要である。この観点で今回、分子型別、全ゲノム解析結果ともでMSMとheterosexualsとが基本的には互いに分離できるコミュニティであることが示された意義は大きい。
全ゲノム解析から抽出された、近縁関係にある日本、中国株を細分できる一塩基置換候補は、近隣国からの輸入例を簡便に検出するマーカーツールとして活用できる可能性があり、今後は今回の全ゲノム解析には成功しなかった検体を含め、この塩基置換の有無を網羅的に解析し、まずその有用性を確定させることが重要であることが示された。