Reproducibility of a Fecal Occult Blood Test Device for Gut Microbiota Analyses

Commensal bacteria and other microbial organisms (the microbiota), particularly in the intestines, are centrally related to nutrition, metabolism, immunity, inflammation, and endocrine balance. As an initial step toward possible establishment of a biobank of feces that could be used for prospective studies of the relationship of microbiota to cancer and other conditions, we propose a study to evaluate whether fecal microbiota, as well as microbial enzyme expression and function, are reproducibly represented in feces that has been collected with a device that is widely used for fecal occult blood testing (FOBT-CHEK oc). To do so, this study will recruit a convenience sample of 50 volunteers from DCEG and others at NIH. From a single stool, each participant will provide 16 aliquots of feces, half collected with FOBT-CHEK oc and the rest with a larger Sarstedt device. A urine sample and a brief self-administered questionnaire on antibiotics and other medications, serious chronic diseases, and major cancer risk factors will also be obtained. The aliquots will be used for microbiome pyrosequencing, beta-glucuronidase and beta-glucosidase expression and enzymatic activity. Variance within and between collection devices, as well as between individuals, will be quantified. This study will provide insight and quantitative estimates that will be required for formal studies of the relationship of the fecal microbiome to cancer. Under an amendment, to examine the ability of selected antibiotics to stabilize fecal microbial populations when they have been stored at 3 or 7 days prior to freezing, 10 of the same volunteer participants will be asked to provide aliquots of a second stool specimen. Differences between immediate and delayed freezing with or without the antibiotics will be tested by analysis of variance. Under an amendment, up to 100 participants will be enrolled to examine reproducibility of the microbiota with a used commercial colorectal cancer screening device and the stability of the microbiota within individuals over four years, participants will be asked to collect specimens during 2014, exactly as was done during 2010. Assays and anlyses will be analogous to those performed previously.