Vice President of Clinical and Regulatory Hygieacare Inc. Norfolk, VA
Orly Levitan, PhD1, Dawn B. Burleson, RN, MBA1, David A. Johnson, MD, MACG2; 1Hygieacare Inc., Norfolk, VA; 2Eastern Virginia Medical School, Norfolk, VA
Introduction: The gut microbiota is a major factor in managing health and diseases. There are numerous studies discussing the gut microbiome, however, they are mainly based on stool samples. These samples represent only the microbiome of the sigmoid. Here we compare the microbial diversity of stool samples versus inner-colonic effluent samples collected prospectively during high-volume water colonic irrigation. Methods: Samples were collected from 11 participants (mean age: 66, min–41, max-78) during an IRB-approved clinical trial. All patients underwent high-volume colon irrigation before screening colonoscopy. The inner colonic samples (n=35) were collected three times during the prep as changes were noted in effluent appearance, to represent the left, transverse and right colon. Stool samples were collected by patients in their homes (n=11). Samples were immediately stabilized and stored following standard procedures and analyzed by PCR amplicon for bacterial rRNA (16SV4). Results: Bacterial communities detected in inner colonic samples were significantly different than those of stool samples. Of all bacterial strains detected, a third of the strains (n=344) were unique to the inner colonic samples, with a unique contribution from the different colonic biogeographic locations. We detected a decrease in the species abundance of Firmicutes and an increase in Proteobacteria when comparing stool to inner-colonic samples, without a significant change in Bacteriodetes. Species of other phyla were more abundant in the inner-colonic samples. There was a clear biogeography gradient of bacteria along the colon, where the overall microbial diversity in each sample decreases towards the proximal colon. The phylogeny of the microbiota community in all stool samples looks relatively similar regardless of the patient. Discussion: There are distinctive and large differences between the stool and inner-colonic samples. For most patients, there is a detectable phylogenetic progression with a predictable, yet personal, trajectory. The patented process of collection of microbial samples using a high-volume water colonic irrigation is currently the only way of obtaining microbiome information from within the colon, non-invasively, and without the effects of oral prep purgatives. The significant difference between the samples detected in this study suggests that obtaining information from inner-colonic communities can be imperative for developing personalized medicine.
Figure 1- A comparison of the inner sample diversity (alpha diversity by Simpson index) of the microbiome community of the different samples: stool (n=11) and three inner-colonic samples representing the left (n=13), transverse (n=11) and right (n=11) colon.
Figure 2 – Phylogenetic species diversity between samples (beta diversity) (n=46) represented by PCoA weighted and unweighted Unifrac analysis. The phylogenetic spread in the multivariance space of the weighted analysis explains approximately 50% of the population diversity of the inner-colonic samples (n-35) diversity and is much wider than the phylogenetic difference of the stool samples.
Figure 3 - A Venn diagram of the unique and shared species between stool and inner-colonic samples (by species presence and absence) and the species distribution of each group of species in the phyla taxonomic rank (n=11 for stool samples, n=35 for inner-colonic samples).
Disclosures: Orly Levitan: Hygieacare Inc. – Employee, Stockholder/Ownership Interest (excluding diversified mutual funds). Dawn Burleson: Hygieacare Inc. – Consultant, Stockholder/Ownership Interest (excluding diversified mutual funds). David Johnson: CEGX – Consultant. CRH MEDICAL – Advisory Committee/Board Member. HYGIeaCare – Advisory Committee/Board Member. ironwood – Consultant. MEDSCAPE – Advisory Committee/Board Member.