Oral Microbial Biomarkers in Crohn’s Disease in Children

Objectives:  Inflammatory Bowel Diseases (IBDs) are a group of diseases involving chronic inflammatory responses to the microbiota in genetically susceptible individuals. Oral manifestations are sometimes present in children with Crohn's disease (CD). Previously, we found a significant decrease in overall diversity in the oral microbiome of pediatric CD. We hypothesize that specific microbial species in the oral cavity can differentiate patients with Crohn's Disease from those with ulcerative colitis or health.

Methods: 114 subjects were recruited from the Children's Hospital Boston.  Tongue and buccal mucosal brushings from healthy controls, CD, and ulcerative colitis (UC) patients were previously analyzed using The Human Oral Microbe Identification Microarray (HOMIM). 9 taxa were significantly elevated in the oral mucosa of CD and 10 taxa were significantly decreased as compared to healthy controls. Candidate microbial biomarkers identified from these HOMIM analyses were verified using qPCR under standard conditions, using DNA from a subset of the initial specimens (10 patients with CD, 10 with UC, 10 controls).

Results: Gemella morbillorum, a candidate species that was decreased in CD, was 0.44 fold lower (p<0.002) from buccal samples. Streptococcus parasanguis, a candidate species that was elevated in CD, was 2.2 fold increased (p<0.0007) in tongue brushings. Results were compared to levels of all taxa or Fusobacterium nucleatum, a species equally present in all samples.

Conclusions: Our microarray studies suggest that children with CD have a different oral microbiome than healthy children.  Candidate oral microbial species that differentiate CD from children without inflammatory bowel disease were verified using qPCR.  The remaining candidate species are presently being evaluated using qPCR. Based on our results, these microbial IBD signatures can be used to develop predictive models for IBD (e.g., screening and diagnosis).  Supported by #5T32DK007477-27, CCFA, HITI/ Helmsley Charitable Trust Pilot Grants Program, and the Rasmussen and MacInnes families.