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Microbiological Comparison of Two Brothers with Familial Adenomatous Polyposis
Kathleen M. Schieffer^*1, Justin Wright², Regina Lamendella², Leonard Harris¹, Sue Deiling¹, Walter Koltun^1
1Surgery, Pennsylvania State University College of Medicine, Hershey, PA; ²Biology, Wright Labs LLC, Juniata College, Huntingdon, PA

Introduction: Familial adenomatous polyposis (FAP) is an autosomal dominant disease which can cause the development of many adenomatous polyps in the colon. One method of treatment is proctocolectomy with ileal pouch anal anastomosis (IPAA). IPAA is also recommended for patients with ulcerative colitis. About 50% of UC patients with an ileal pouch develop inflammation of the pouch, known as pouchitis, during their lifetime. However, patients with FAP rarely develop pouchitis. Pouchitis is commonly treated with antibiotics; therefore, differences in the microbiota composition of the pouch have been studied between individuals with UC and FAP. Reduced concentrations of Bacteroides spp. and Faecalibacterium prausnitzii have been found to be associated with UC patients. A unique situation presented with two brothers who have a strong familial history of FAP and had IPAA surgery in 2009. At the time of surgery, both siblings had 100s of sessile polyps throughout the stomach and colon. Since surgery, one sibling has developed multiple cases of pouchitis. This study sought to address the hypothesis: The bacterial composition of the rectum and terminal ileum, excised during IPAA surgery, differs between the two brothers, predicting development of pouchitis.
Methods: Tissue was stored at -80°C since the time of surgery. DNA was extracted using the Qiagen DNeasy Blood and Tissue Kit. 16S rRNA sequencing of the V4 region was performed on the Illumina MiSeq, and over 450,000 quality filtered reads were analyzed within QIIME-1.9.0.
Results: Both terminal ileum and rectum were studied since the ileal pouch is constructed from the ileum and functions as the rectum. Changes in the microbiota over time to a normal “colonic” phenotype have been described in patients with IPAA. In the rectum, the sibling with a history of pouchitis showed reduced abundance of Ruminococcaceae, Bacteroides spp., Lachnospiraceae, Clostridiales, and Faecalibacterium prausnitzii compared to the sibling without pouchitis. A similar profile was seen in the terminal ileum. No significant differences were described for environmental or surgical factors.
Conclusions: FAP patients with an ileal pouch rarely develop pouchitis and presentation of two brothers with similar demographics and environmental factors allowed for an interesting comparison of the microbiota. In this case, the sibling that developed pouchitis had a microbiota composition of the rectum and terminal ileum that differed and more strongly represented that of UC patients with active pouchitis. This suggests that the microbiota composition at the time of surgery may be able to predict if there is a predisposition to pouchitis development, especially in FAP patients.

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