Understanding How Candida albicans Colonizes the Human Gut

Approximately 80% of individuals harbor the fungus Candida albicans within their gastrointestinal tract. While in most cases it remains a benign inhabitant without causing noticeable issues, under certain conditions it can transform into a pathogenic microbe, leading to severe infections in organs such as the urinary tract, lungs, and brain. Gaining insight into the mechanisms by which C. albicans establishes itself in the gut is essential for developing strategies to prevent its harmful overgrowth.

Recent research utilizing mouse models has shed light on this process. Scientists at Baylor College of Medicine, along with international partners, discovered unexpected factors that facilitate the colonization and persistence of C. albicans in the gut environment. Notably, their studies, published in Microbiology Spectrum, revealed that even in healthy conditions without prior antibiotic treatment or immune suppression, a clinical strain of C. albicans (called CLCA10) can survive in the mouse gut for at least 58 days. Importantly, this persistent colonization does not lead to weight loss, inflammation, or disruptions in the gut’s bacterial community.

The research countered previous assumptions that factors like immune suppression or disruption of the microbiota were necessary for colonization. Instead, C. albicans was primarily associated with the gut’s contents and mucus layer, making it distinct from other fungi that typically do not colonize the human gut. The study further identified that hyphal factors—specifically certain proteins such as candidalysin, Als3, and Hwp1—are crucial for the fungus to establish and maintain its presence. Strains lacking these proteins showed significantly reduced colonization ability.

Interestingly, the production of the toxin candidalysin, which is known to damage host tissues and trigger immune responses, was found to be essential for colonization, contrary to initial expectations. This highlights the complex role of fungal virulence factors in colonization and persistence.

The findings suggest that targeting these hyphal-associated proteins could be a promising approach to reduce C. albicans colonization in the gut. Such strategies may help prevent invasive infections and address the broader health risks associated with fungal overgrowth. Overall, this research enhances our understanding of host-microbe interactions and the specific attributes that enable C. albicans to become a persistent member of the gut microbiota.

Source: https://medicalxpress.com/news/2025-07-common-fungus-candida-albicans-colonizes.html