The Gut Mycobiome in Inflammatory Bowel Disease: Reframing Candida as a Signal of Ecosystem Disruption

Growing interest in the gut mycobiome has renewed focus on Candida spp. in inflammatory bowel disease (IBD). Yet, fecal detection remains difficult to interpret, given its uncertain relationship with intestinal inflammation. This narrative review synthesizes historical, mechanistic, observational, and interventional evidence to distinguish colonization, relative abundance, mucosal invasion, virulence transitions, and potential contributions to IBD.

PubMed, Scopus, the Cochrane Library, and Google Scholar were searched, focusing on human studies and major mechanistic or interventional contributions. The final synthesis included 43 studies, 41 research articles, and two historical monographs.

Fungal alterations in IBD are heterogeneous and method-dependent across studies. Longitudinal cohorts have associated increased relative abundance of the genus Candida with active disease, but findings have not been consistently replicated across populations. Experimental evidence suggests that fungal expansion, morphology, and strain-specific virulence may trigger inflammation in selected settings, although stool sequencing cannot establish viability, invasion, morphology, or causality. Antifungal therapy, fecal microbiota transplantation, and nutraceutical approaches may modify microbial or inflammatory markers, but consistent clinical benefits remain unproven.

Fecal detection of Candida spp. should generally be interpreted as a context-dependent signal of disrupted bacterial-fungal-immune interactions, not as evidence of infection or a compelling indication for antifungal treatment.