Human gut bifidobacteria inhibit the growth of the opportunistic fungal pathogen Candida albicans. Issue 10 (25th August 2022)

• Record Type: Journal Article
• Authors: Ricci, Liviana; Mackie, Joanna; Donachie, Gillian E; Chapuis, Ambre; Mezerová, Kristýna; Lenardon, Megan D; Brown, Alistair J P; Duncan, Sylvia H; Walker, Alan W
• Is Part Of: FEMS microbiology ecology. Volume 98:Issue 10(2022)
• Publication Date: 2022-08-25
• Subjects: human gut microbiota -- bifidobacteria -- colonization resistance -- Candida albicans -- short chain fatty acids -- lactate -- pH; Microbial ecology -- Periodicals; Microbiology -- Periodicals; 579.17
• DOI: 10.1093/femsec/fiac095
• Languages: English
• ISSNs: 0168-6496

Abstract

Abstract: The human gut microbiota protects the host from invading pathogens and the overgrowth of indigenous opportunistic species via a process called colonization resistance. Here, we investigated the antagonistic activity of human gut bacteria towards Candida albicans, an opportunistic fungal pathogen that can cause severe infections in susceptible individuals. Coculture batch incubations of C. albicans in the presence of faecal microbiota from six healthy individuals revealed varying levels of inhibitory activity against C. albicans . 16S rRNA gene amplicon profiling of these faecal coculture bacterial communities showed that the Bifidobacteriaceae family, and Bifidobacterium adolescentis in particular, were most correlated with antagonistic activity against C. albicans . Follow-up mechanistic studies performed under anaerobic conditions confirmed that culture supernatants of Bifidobacterium species, particularly B. adolescentis, inhibited C. albicans in vitro . Fermentation acids (FA), including acetate and lactate, present in the bifidobacterial supernatants were important contributors to inhibitory activity. However, increasing the pH of both bacterial supernatants and mixtures of FA reduced their anti- Candida effects, indicating a combinatorial effect of prevailing pH and FA. This work, therefore, demonstrates potential mechanisms underpinning gut microbiome-mediated colonization resistance against C. albicans, and identifies particularly inhibitory components such as bifidobacteria and FA as targets for further study. Abstract : This study showed that faecal microbiota vary in their ability to inhibit the fungal pathogen Candida albicans, and identified bifidobacteria, and their fermentation acids, as inhibitory gut microbiota components.