Candida albicans colonization of the gastrointestinal tract: A double-edged sword

Abstract

Candida albicans is not only a common commensal of the vaginal and gastrointestinal tract (GIT) of humans, but also an important cause of infections worldwide and is therefore considered an opportunistic pathogen. C. albicans can cause superficial but also more severe, frequently life-threatening, systemic infections. The latter may occur when the microbiota is disturbed and immune defenses are compromised, thus allowing the dissemination of the fungus from commensal pools, in particular the GIT, to vital organs. Therefore, gastrointestinal C. albicans colonization can be seen as a predisposing factor of life-threatening infections. However, recent evidence indicates that commensal coexistence of C. albicans with the human host is not only detrimental. In fact, beneficial effects of C. albicans colonization to human health, most likely, have been an evolutionary pressure for its establishment as a commensal. Here, we review recent studies that demonstrate both beneficial and detrimental effects of this pathobiont to human health upon colonization of the human gut.