RESUMEN
AIM: To investigate the accuracy of fungal dysbiosis in mucosa and stool for predicting the diagnosis of Crohn's disease (CD). METHODS: Children were prospectively enrolled in two medical centers: one university hospital and one private gastroenterology clinic in the city of Riyadh, Kingdom of Saudi Arabia. The children with confirmed diagnosis of CD by standard guidelines were considered cases, and the others were considered non-inflammatory bowel disease controls. Mucosal and stool samples were sequenced utilizing Illumina MiSeq chemistry following the manufacturer's protocols, and abundance and diversity of fungal taxa in mucosa and stool were analyzed. Sparse logistic regression was used to predict the diagnosis of CD. The accuracy of the classifier was tested by computing the receiver operating characteristic curves with 5-fold stratified cross-validation under 100 permutations of the training data partition and the mean area under the curve (AUC) was calculated. RESULTS: All the children were Saudi nationals. There were 15 children with CD and 20 controls. The mean age was 13.9 (range: 6.7-17.8) years for CD children and 13.9 (3.25-18.6) years for controls, and 10/15 (67%) of the CD and 13/20 (65%) of the control subjects were boys. CD locations at diagnosis were ileal (L1) in 4 and colonic (L3) in 11 children, while CD behavior was non-stricturing and non-penetrating (B1) in 12 and stricturing (B2) in 3 children. The mean AUC for the fungal dysbiosis classifier was significantly higher in stools (AUC = 0.85 ± 0.057) than in mucosa (AUC = 0.71 ± 0.067) (P < 0.001). Most fungal species were significantly more depleted in stools than mucosal samples, except for Saccharomyces cerevisiae and S. bayanus, which were significantly more abundant. Diversity was significantly more reduced in stools than in mucosa. CONCLUSION: We found high AUC of fungal dysbiosis in fecal samples of children with CD, suggesting high accuracy in predicting diagnosis of CD.
Asunto(s)
Enfermedad de Crohn/diagnóstico , Disbiosis/epidemiología , Heces/microbiología , Hongos/aislamiento & purificación , Microbioma Gastrointestinal/genética , Adolescente , Estudios de Casos y Controles , Niño , Enfermedad de Crohn/epidemiología , Enfermedad de Crohn/microbiología , Enfermedad de Crohn/patología , ADN de Hongos/genética , ADN de Hongos/aislamiento & purificación , Disbiosis/microbiología , Femenino , Hongos/genética , Humanos , Incidencia , Mucosa Intestinal/microbiología , Mucosa Intestinal/patología , Masculino , Pronóstico , Estudios Prospectivos , Arabia Saudita/epidemiologíaRESUMEN
Background and Aims: Although increasing evidence suggests a role for fungi in inflammatory bowel disease [IBD], data are scarce and mostly from adults. Our aim was to define the characteristics of fungal microbiota in newly diagnosed treatment-naïve children with Crohn's disease [CD]. Methods: The children referred for colonoscopy were prospectively enrolled in the study at King Khalid University Hospital, King Saud University, and Al Mofarreh Polyclinics in Riyadh. Tissue and stool samples were collected and frozen till sequencing analysis. The children with confirmed CD diagnosis were designated as cases and the others as non- IBD controls; 78 samples were collected from 35 children [15 CD and 20 controls]. Statistical analysis was performed to investigate CD associations and diversity. Results: CD-associated fungi varied with the level of phylogenetic tree. There was no significant difference in abundance between normal and inflamed mucosa. Significantly abundant CD-associated taxa included Psathyrellaceae [p = 0.01], Cortinariaceae [p = 0.04], Psathyrella [p = 0.003], and Gymnopilus [p = 0.03]. Monilinia was significantly depleted [p = 0.03], whereas other depleted taxa, although not statistically significant, included Leotiomycetes [p = 0.06], Helotiales [p = 0.08], and Sclerotiniaceae [p = 0.07]. There was no significant difference in fungal diversity between CD and controls. Conclusions: We report highly significant fungal dysbiosis in newly diagnosed treatment-naïve CD children. Depleted and more abundant taxa suggest anti-inflammatory and pro-inflamatory potentials, respectively. Further studies with larger sample size and including functional analysis are needed to clarify the significance of the fungal community in the pathogenesis of CD.