P067 INVESTIGATION OF THE PRESENCE OF MYCOBACTERIUM AVIUM SSP. PARATUBERCULOSIS IN CHILDREN WITH CROHN DISEASE USING QUANTITATIVE DNA SEQUENCE-BASED APPROACHES

• Published in: Inflammatory bowel diseases Vol. 24; no. suppl_1; p. S25
• Main Authors: Hofstaedter, Casey E, Conrad, Maire A, Misic, Ana M, Fecteau, Marie-Eve, Kelsen, Judith, Bittinger, Kyle, Beiting, Daniel P, Pitta, Dipti, Sweeney, Raymond W, Baldassano, Robert
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 18-01-2018
• ISSN: 1078-0998; 1536-4844
• DOI: 10.1093/ibd/izy019.073

Abstract
Background
Mycobacterium avium ssp. paratuberculosis (MAP) has been suspected to play a role in Crohn disease (CD) pathogenesis. Prior studies of MAP detection in dairy cows have been more extensively investigated, successfully detecting the organisms by culture and PCR. These studies have shown the organism to be the causative agent in Johne's disease, an enteritis in ruminants that is histopathologically similar to CD.
Aim
We aim to use techniques which successfully detect MAP in cow feces and apply them to human feces and intestinal biopsy samples of patients with CD and healthy controls to see if MAP infection is correlated with active disease in children with CD.
Methods
Using feces and intestinal biopsy samples from known MAP-positive and negative calves, we performed several Mycobacterium-specific DNA extraction methods. We used quantitative PCR and DNA-sequencing methods. We applied these methods to samples from pediatric patients with CD and non-CD controls. Two samples were taken from each patient: one from the terminal ileum, and the other from either the cecum, left colon, or rectum. Five out of the eight patients were treatment naïve at the time of sample collection. The other three received antibiotics leading up to sample collection.
Results
We correctly identified the presence of MAP in intestinal biopsies from infected dairy calves using qPCR, which aligned with culturing data from these biopsies. In our small subset of samples, we were unable to detect the presence of MAP in CD patients by any of these techniques.
Conclusion
The detection of MAP from intestinal biopsies in calves demonstrates that we can use these techniques to quantitatively identify the number of organisms in intestinal biopsies, without the use of culture-based methods. We have confirmed the difficulty in detecting this organism in humans. Work is ongoing to improve the sensitivity of our techniques and increase the number of patient samples tested.