Related Experiment Video
Updated: Feb 21, 2026
Quantifying the Antifungal Activity of Peptides Against Candida albicans
Published on: January 13, 2023
Pseudomonas phage inhibition of Candida albicans
Hasan Nazik1,2, Lydia-Marie Joubert3, Patrick R Secor4
1Division of Infectious Diseases, Department of Medicine, Stanford University Medical School, Stanford, CA, USA.
Abstract:
Pseudomonas aeruginosa (Pa) and Candida albicans (Ca) are major bacterial and fungal pathogens in immunocompromised hosts, and notably in the airways of cystic fibrosis patients. The bacteriophages of Pa physically alter biofilms, and were recently shown to inhibit the biofilms of Aspergillus fumigatus. To understand the range of this viral-fungal interaction, we studied Pa phages Pf4 and Pf1, and their interactions with Ca biofilm formation and preformed Ca biofilm. Both forms of Ca biofilm development, as well as planktonic Ca growth, were inhibited by either phage. The inhibition of biofilm was reversed by the addition of iron, suggesting that the mechanism of phage action on Ca involves denial of iron. Birefringence studies on added phage showed an ordered structure of binding to Ca. Electron microscopic observations indicated phage aggregation in the biofilm extracellular matrix. Bacteriophage-fungal interactions may be a general feature with several pathogens in the fungal kingdom.
Insights
Bacteriophages, viruses that infect bacteria, were found to inhibit the growth of Candida albicans (Ca) biofilms. This anti-fungal effect, potentially by limiting iron availability, suggests broader phage-fungal interactions in infections.
Area of Science:
- Microbiology
- Virology
- Biochemistry
Background:
- Pseudomonas aeruginosa (Pa) and Candida albicans (Ca) are significant pathogens in immunocompromised individuals, particularly in cystic fibrosis airways.
- Pa bacteriophages have demonstrated biofilm disruption capabilities and inhibited Aspergillus fumigatus biofilms.
Purpose of the Study:
- To investigate the interactions between Pa phages (Pf4 and Pf1) and Ca biofilm formation and pre-formed biofilms.
- To explore the mechanism behind phage-mediated inhibition of Ca growth and biofilm development.
Main Methods:
- Studied the effect of Pa phages Pf4 and Pf1 on planktonic Ca growth and biofilm development.
- Investigated the role of iron in reversing phage-induced inhibition.
- Utilized birefringence and electron microscopy to observe phage-Ca interactions.
Main Results:
- Both Pa phages Pf4 and Pf1 inhibited Ca biofilm formation and planktonic growth.
- Iron supplementation reversed the inhibitory effects of phages on Ca biofilms.
- Birefringence and electron microscopy revealed ordered phage binding to Ca and aggregation within the biofilm matrix.
Conclusions:
- Bacteriophages can inhibit Candida albicans growth and biofilm formation, suggesting a novel antiviral-fungal interaction.
- Phage inhibition of Ca may be mediated by iron sequestration.
- These findings indicate that bacteriophage-fungal interactions could be a widespread phenomenon with implications for polymicrobial infections.
