Integrated Analysis of Gut Mycobiome Dysbiosis and Functional Alterations Reveals Potential Diagnostic Biomarkers for Active Ulcerative Colitis
This study characterizes the gut mycobiome landscape in active ulcerative colitis (UC) using ITS1 sequencing, revealing a profound contraction in $\alpha$-diversity and a significant phylogenetic shift. We identified a signature dysbiosis marked by the expansion of opportunistic pathobionts, specifically Saccharomyces (31.9%) and Candida (22.4%), with the Candida-to-Saccharomyces ratio emerging as a key indicator of intestinal homeostasis disruption. A Random Forest diagnostic model incorporating five key fungal genera achieved an exceptional AUC of 0.966 (95% CI: 0.924_1.000), providing a highly accurate, non-invasive tool for UC monitoring. These findings underscore the role of the fungal "dark matter" in UC pathogenesis and offer new avenues for mycobiome-targeted precision diagnostics.