J Crohns Colitis. 2015 Nov 15. pii: jjv209. [Epub ahead of print]
Fungal dysbiosis in mucosa-associated microbiota of Crohn's disease patients.
Liguori G1, Lamas B2, Richard ML3, Brandi G4, Da Costa G3, Hoffmann TW3, Di Simone MP1, Calabrese C1, Poggioli G1, Langella P3, Campieri M1, Sokol H5.
BACKGROUND & AIMS:
Gut microbiota is involved in many physiological functions and its imbalance is associated with several diseases, particularly with inflammatory bowel diseases.
Mucosa-associated microbiota could have a key role in induction of host immunity and in inflammatory process. Although the role of fungi has been suggested in inflammatory disease pathogenesis, the fungal microbiota has not yet been deeply explored.
Here we analyzed the bacterial and fungal composition of the mucosa associated microbiota of Crohn's disease patients and healthy subjects.
Our prospective, observational study evaluated bacterial and fungal composition of mucosa-associated microbiota of 23 Crohn's disease patients (16 in flare, 7 in remission) and 10 healthy subjects using 16S (MiSeq) and ITS2 (pyrosequencing) sequencing, respectively. Global fungal load was assessed by real time quantitative PCR.
Bacterial microbiota in Crohn's disease patients was characterized by a restriction in biodiversity with an increase of Proteobacteria and Fusobacteria. Global fungi load was significantly increased in Crohn's disease flare compared to healthy subjects (p < .05). In both groups, the colonic mucosa-associated fungal microbiota was dominated by Basidiomycota and Ascomycota phyla.
Cystofilobasidiaceae family and Candida glabrata species were overrepresented in Crohn's disease.
Saccharomyces cerevisiae and Filobasidium uniguttulatum species were associated with non-inflamed mucosa whereas Xylariales order was associated with inflamed mucosa.
Our study confirms the alteration of the bacterial microbiota and is the first demonstration of the existence of an altered fungal microbiota in Crohn's disease patients suggesting that fungi may play a role in its pathogenesis.