抗生物質汚染が両生類の減少を加速させる可能性(Antibiotic pollution could accelerate amphibian decline by turning a potential solution into a threat)

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2025-09-12 ウィスコンシン大学マディソン校(UW-Madison)

ウィスコンシン大学マディソン校の研究によると、水域に流入する抗生物質汚染が両生類の衰退を加速させる可能性がある。カエルなどを死に至らせる真菌 Bd(ツボカビ病原体) は、本来は水中の細菌が産生する化学物質によって抑制されうる。しかし抗生物質汚染下で適応した シュードモナス属細菌 は、この防御的化合物の生成が変化し、逆にBdの成長を促進、オタマジャクシの感染率を6倍に増加させた。一方、バイオフィルム形成株では効果が逆転するなど、細菌の生活様式も重要因子であることが判明。従来「自然由来の微生物を利用した感染防御」が有望視されていたが、環境履歴を無視すると逆効果になり得ると警告している。成果は Scientific Reports に発表され、抗生物質汚染と生態系保全の関連に新たな視点を与える。

<関連情報>

抗生物質に対する微生物の反応は、病気の転帰の方向を不可解に変化させる Microbial responses to antibiotics cryptically shift the direction of disease outcomes

Isabela Velasquez,Kyra Ricci,Eve Milusich,Bryon F. Tuthill II,Karin Sauer,Obed Hernández-Gómez & Jessica Hua
Scientific Reports  Published:02 July 2025
DOI:https://doi.org/10.1038/s41598-025-02930-y

抗生物質汚染が両生類の減少を加速させる可能性(Antibiotic pollution could accelerate amphibian decline by turning a potential solution into a threat)

Abstract

Diseases are emerging at unprecedented rates, prompting global efforts to understand factors shaping disease outcomes. Microbes associated with hosts and the environment influence disease by secreting antipathogenic metabolites, hindering pathogen success. However, antibiotic contamination and costs associated with microbial responses to antibiotics may reduce antipathogenic efficacy. We investigated how antibiotic tolerance influences the antipathogenic properties of metabolites produced by Pseudomonas aeruginosa using in vitro and in vivo experiments. We found that metabolites from antibiotic-non-tolerant P. aeruginosa strains retained their antipathogenic properties and inhibited the growth of Batrachochytrium dendrobatidis (Bd), an amphibian fungal pathogen responsible for amphibian declines worldwide. In contrast, metabolites from P. aeruginosa strains that developed antibiotic tolerance promoted Bd growth and exacerbated infection severity. These patterns were consistent in vitro and in vivo. We also ran toxicological and small molecule analyses of microbial metabolites, and findings suggest the divergent experimental outcomes may stem from differences in metabolite toxicity and profiles between strains. These findings underscore the hidden consequences of interactions between microbial responses to environmental changes and pathogens on infectious disease dynamics and highlight the need to integrate environmental change and eco-evolutionary perspectives into disease research.

生物環境工学
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