Establishment of culture methods and genetic diversity of a novel microorganism (IOLA) lurking in the human respiratory tract

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K07491
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 49050:Bacteriology-related
• Research Institution: University of Occupational and Environmental Health, Japan
• Principal Investigator: FUKUDA Kazumasa 産業医科大学, 医学部, 准教授 (40389424)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 新規感染性微生物 / 呼吸器感染症 / 小児鼻汁 / 16S rRNA遺伝子

Outline of Final Research Achievements

A novel bacterium, IOLA, which has not yet been established culture-method and which properties are unknown, was detected in 5.4% (103/1,920 samples) of pediatric nasal discharge samples. There was no regional or seasonal difference in the detection of IOLA, nor was there any difference in frequency of detection based on symptoms. Although the pathogenicity of IOLA is still unknown, the IOLA 16S rRNA gene sequence has five phylotypes, strongly suggesting that there are differences in the pathogenicity of each phylotype. It was also shown that IOLA can be propagated by co-culture with human-derived airway epithelial cells. The results obtained in this study are very useful information for establishing a culture method of IOLA and elucidating its pathogenicity.

Free Research Field

病原微生物学

Academic Significance and Societal Importance of the Research Achievements

慢性下気道感染患者由来の気管支肺胞洗浄液から検出された細菌IOLAは、病原性が強く疑われる科のレベルで新規な細菌である。しかし、未だに培養法が確立されておらず、その性状についてはほとんど不明である。IOLAは培養法で検出できないだけではなくグラム染色でも検出できず、医療従事者はその存在にすら気づくことができない状況であり、IOLAの病原性解明は喫緊の課題である。本研究ではIOLA検出頻度や遺伝的多様性等を明らかにし、身近な病原体候補であることを明らかにした。本結果は、IOLAの培養法の確立、性状や病原性の解析に寄与する情報であり、今後IOLAと原因不明疾患の相関解明等に役立つと考えられる。