鼻腔マイクロバイオーム研究:ビオチン欠乏が病原菌制御に役立つ可能性(Nasal Microbiome: Resource Scarcity as Opportunity)

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2025-11-25 ミュンヘン大学(LMU)

LMUミュンヘンの研究チームは、ヒトの鼻腔微生物叢が「資源の乏しい環境」を逆に活かして生存戦略を構築していることを明らかにした。鼻腔は乾燥・低温・栄養不足の過酷な環境だが、細菌は代謝負荷の大きい酵素を削減し、互いに代謝物を補完し合う“協力型ネットワーク”を形成することで適応していた。特に、アミノ酸や補酵素の不足を他菌種が産生する代謝物で補う仕組みが確認され、微生物間の相互依存性が生態系の安定に寄与していた。研究は培養実験とゲノム解析を組み合わせ、鼻腔細菌が資源制限下で競争より協調を選ぶ進化的背景を示したもので、抗菌薬耐性の制御や新たな微生物療法の開発にも応用が期待される。

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黄色ブドウ球菌 の鼻腔常在菌に対する競争力はビオチンの生合成と獲得に依存する Competitive fitness of Staphylococcus aureus against nasal commensals depends on biotin biosynthesis and acquisition

Kevser Bilici, David Gerlach, Laura Camus, Simon Heilbronner
The ISME Journal  Published:04 November 2025
DOI:https://doi.org/10.1093/ismejo/wraf248

鼻腔マイクロバイオーム研究:ビオチン欠乏が病原菌制御に役立つ可能性(Nasal Microbiome: Resource Scarcity as Opportunity)
Graphical Abstract

Abstract

The human nasal microbiome can serve as a reservoir for pathogens. In particular, the opportunistic pathogen Staphylococcus aureus can be a member of the nasal microbiome increasing the risk of subsequent infections. The nasal carriage of S. aureus is known to be positively and negatively impacted by nonpathogenic species, suggesting interactions between the pathogen and commensals, but the underlying molecular mechanism remains largely unclear. Herein we demonstrate that S. aureus competes with nasal commensals for the coenzyme biotin. Biotin is crucial for all living organisms and we show that depletion of biotin impairs S. aureus growth and membrane integrity. We found the nasal cavity to be a biotin-limited environment, suggesting competition for the coenzyme within the microbiome. For some nasal commensals and S. aureus, we observed biotin prototrophy and all strains released biotin into the environment. In contrast, other commensals and especially coagulase-negative staphylococci (CoNS) were found to be biotin auxotrophs and strongly reliant on prototrophic strains under biotin-limited conditions. We show that high-affinity biotin uptake systems are used by prototrophic and auxotrophic strains alike and represent crucial factors to optimize competitive fitness of species in co-culture. Together, our data show that biotin-mediated interactions occur between the species of the human nasal microbiome and provide evidence for interspecies competition and co-dependency.

医療・健康
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