Prevalence and molecular epidemiology of Legionnaires' disease

• Project/Area Number: 20K18922
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 58020:Hygiene and public health-related: including laboratory approach
• Research Institution: Toyama Institute of Health
• Principal Investigator: Kanatani Jun-ichi 富山県衛生研究所, 細菌部, 主任研究員 (80463131)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Project Status: Completed (Fiscal Year 2023)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2023: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2022: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2021: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2020: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
• Keywords: レジオネラ / ゲノム分子疫学解析 / 分子疫学

Outline of Research at the Start

現在普及しているレジオネラ症診断用の尿中抗原検査試薬は、レジオネラ・ニューモフィラ血清群1（Lp1）以外の菌種・血清群に対する感度は著しく低い。そのため、Lp1以外のレジオネラ属菌に感染している患者は把握されていない。本研究では、前向き調査により潜在的なレジオネラ症患者を積極的な喀痰培養検査によって診断し、国内における実際のレジオネラ症患者の罹患率を推計する。また、患者実態の把握を通じて、これまで不明であったLp1以外を原因菌とするレジオネラ症患者の感染源を解明する。

Outline of Final Research Achievements

The objective of this study is to diagnose potential Legionnaires' disease patients through proactive sputum culture testing and to elucidate the sources of infection. Culture testing was conducted on respiratory specimens from 189 cases, resulting in the isolation of Legionella pneumophila serogroup 2 (Lp2) from two specimens. Subsequent phylogenetic analysis of the whole genome sequences of the Lp2 isolates including those from various environmental sources revealed that clinical isolates were closely related to the isolates derived from puddles. Therefore, it was suggested that patients infected with these isolates might have been infected in locations other than bathing facilities.

Academic Significance and Societal Importance of the Research Achievements

従来の尿中抗原検査試薬はLegionella pneumophila血清群1（Lp1）以外の菌種・血清群に対する感度は著しく低いため、Lp1以外のレジオネラ属菌に感染している患者は把握されていない。したがって、現在まで、国内において、Lp1以外を原因菌とする潜在的なレジオネラ症患者の実態はよくわかっていない。本研究により、従来の尿中抗原検査では診断できない、Lp1以外を原因菌とする潜在的なレジオネラ症患者の存在が明らかとなった。

Research Products

• [Journal Article] Correlation between bacterial microbiome and <i>Legionella</i> species in water from public bath facilities by 16S rRNA gene amplicon sequencing (2024)
  • Author(s): Kanatani Jun-ichi、Fujiyoshi So、Isobe Junko、Kimata Keiko、Watahiki Masanori、Maenishi Emi、Izumiyama Shinji、Amemura-Maekawa Junko、Maruyama Fumito、Oishi Kazunori
  • Journal Title: Microbiology Spectrum Volume: 12 Issue: 4
  • DOI: 10.1128/spectrum.03459-23
  • Peer Reviewed / Open Access
• [Journal Article] Detection of Legionella species, the influence of precipitation on the amount of Legionella DNA, and bacterial microbiome in aerosols from outdoor sites near asphalt roads in Toyama Prefecture, Japan (2021)
  • Author(s): Kanatani JI, Watahiki M, Kimata K, Kato T, Uchida K, Kura F, Amemura-Maekawa J, Isobe J.
  • Journal Title: BMC Microbiology Volume: 21(1) Issue: 1 Pages: 215-215
  • DOI: 10.1186/s12866-021-02275-2
  • Peer Reviewed / Open Access
• [Journal Article] 環境水を用いた各種レジオネラ属菌迅速検査法の有用性の評価 (2020)
  • Author(s): 金谷潤一、磯部順子、山口友美、武藤千恵子、淀谷雄亮、飯髙順子、佐々木麻里、田栗利紹、蔡国喜、川野みどり、倉文明、前川純子
  • Journal Title: 日本防菌防黴学会誌 Volume: 48 Pages: 515-522
  • NAID: 40022379553
  • Peer Reviewed
• [Presentation] Characterization of bacterial microbiome in water from public bath, especially focused on Legionella (2022)
  • Author(s): Kanatani JI, Fujiyoshi S, Isobe J, Kimata K, Watahiki M, Maenishi E, Izumiyama S, Amemura-Maekawa J, Maruyama F, Oishi K.
  • Organizer: 10th International Conference on Legionella 2022
  • Int'l Joint Research
• [Presentation] 富山県のレジオネラ症対策における衛生研究所の取り組みと地域連携 (2020)
  • Author(s): 金谷潤一、磯部順子、大石和徳
  • Organizer: 第94回日本感染症学会総会・学術講演会