Digestive Tract Mycobiota: a Source of Infection

The human mycobiome includes 390 fungal species detected on the skin, in the vagina, in the oral cavity, and in the digestive tract that includes 335 species and 158 genera. Among these, 221 species are found only in the digestive tract, 88 only in the oral cavity, and 26 in both. These species belong to 126 genera of yeast and filamentous fungi, of the Ascomycota, Basidiomycota, and Zygomycota phyla. Forty species were identified only by culture, 188 species by molecular techniques, and 19 species with both techniques. Fungal diversity does not differ significantly according to sex but Basidiobolus ranarum is significantly more prevalent in male individuals and Paecilomyces fumosoroseus in female individuals. Fungal diversity is significantly higher in adults than in infants. Only 42 species are identified in the course of inflammatory bowel disease, with 27 species specific to IBD. Twenty-nine are identified in HBV infected patients including 17 specific species, and 11 in HIV-infected patients with the specific Histoplasma capsulatum. Genotyping proved that the gut mycobiome was a source of fungal infection caused by Candida albicans and Candida glabrata. The authors suggest updating the repertoire of the human digestive tract in healthy individuals and patients. Fungal culturomics must be intensified to complete this repertoire.