2026-03-09 ノースカロライナ州立大学（(NC State)）
Image credit: Darryl Leja, NHGRI.
＜関連情報＞
- https://news.ncsu.edu/2026/03/researchers-make-probiotic-safer/
- https://www.nature.com/articles/s42003-026-09763-z
ENA1欠損は、免疫抑制マウス真菌血症モデルにおいて、サッカロミセス・ボウラディ（Saccharomyces ‘boulardii’）プロバイオティクス酵母の毒性を減弱させる ENA1 deficiency attenuates Saccharomyces ‘boulardii’ probiotic yeast virulence in immunosuppressed mouse fungaemia model
Alexandra Imre,Renátó Kovács,Ágnes Jakab,Andrea Harmath,Bálint Németh,Fruzsina Nagy,Lajos Forgács,Dávid Balázsi,László Majoros,Zsigmond Benkő,Nathan Crook,István Pócsi & Walter P. Pfliegler
Communications Biology Published:06 March 2026
DOI:https://doi.org/10.1038/s42003-026-09763-z Unedited version
Abstract
Recently, fungal infections originating from the probiotic Saccharomyces ‘boulardii’ yeast are increasingly reported. Here, we aimed to reveal the background of and to diminish the virulence of this yeast, mitigating infection risks in vulnerable patient groups. Product and human isolates of S. ‘boulardii’ were subjected to in-host selection and their subclone lineages were compared phenotypically to identify target phenotypes and associated genes. More virulent isolates showed signs of selection for high osmotic tolerance in immunosuppressed mouse model, hence the genes NHA1 and ENA1 were deleted in six different ‘boulardii’ backgrounds. Only ENA1 deletion diminished virulence in our mouse fungemia model and it retained the ability for gut colonization and its probiotic characteristics, including similar effects on the gut microbiome in gavaged mice. We also demonstrated the successful substitution of the ENA1 gene with an antilisterial bacteriocin, opening a strategy for safe strains with therapeutic effect. Our strain development approach highlighted the importance of testing various genetic backgrounds and resulted in engineered strains with drastically reduced capability to cause bloodstream infections even in immunosuppressed hosts, establishing the groundwork for safer probiotic yeast therapies in the future.
