Abstract C024: Room temperature stabilization of fecal samples supports important microbiome insights to expand access
Authors: Colameco Savannah , Macklaim Jean M. , Brown Ashlee , Parks Tara Crawford 
Published: December 2023

Analysis of microbial signatures associated with colorectal cancer has potential to improve access and adherence to cancer screening programs through non-invasive sampling, particularly in underserved communities. Lack of reproducibility between studies remains a challenge and has limited the ability to translate research findings into scalable clinical applications. The common practice of storing samples at -80°C/-112°F is inconvenient, often not feasible, and may introduce bias if samples are not handled carefully and consistently. Large-scale screening programs would benefit from room temperature stabilization and sample homogenization at the point of collection, without the logistical considerations for rapid and long-term freezing.  To evaluate the potential of room temperature stability, fecal samples from adult and pediatric individuals were self-collected at home using the OMNIgene™•GUT Dx device with corresponding unstabilized samples stored at -80°C/-112°F. Metagenomics sequencing was utilized to generate microbiome profiles and identify taxa-associated biomarkers relevant to gastrointestinal health and aging. Stabilized samples were compared to freshly collected unstabilized samples (n=18) to evaluate any bias introduced by the stabilizing solution. The same stabilized samples were compared to unstabilized samples stored at -80°C/-112°F to evaluate stability over time. In addition, reproducibility was evaluated by performing DNA extractions in triplicate from ten stabilized fecal samples. Finally, the ability of the room temperature stabilization to capture expected differences between groups was evaluated by comparing adult and pediatric (n=30 per group) samples and looking for known signatures specific to each group. This research demonstrated equivalent stability over time between stabilized samples at room temperature and unstabilized samples stored at -80°C/-112°F, showing preservation of both highly abundant and rare members of the microbial community. Findings indicate that room temperature stabilization does not introduce bias relative to freshly collected unstabilized samples and produces sufficient sample homogenization to yield reproducible microbial profiles. The comparison between adult and pediatric stabilized fecal samples highlights an enrichment for pediatric-specific signatures, such as Bifidobacterium and Veillonella species, and further captures the lower diversity of pediatric samples relative to more developed adult microbiota. These results demonstrate that the OMNIgene™•GUT Dx device enables the preservation of microbial community structure with room temperature stabilization and sample homogenization for use in the detection of biomarkers in fecal samples. Simple logistics of room temperature storage, combined with an easy-to-use self-collection design and compatibility with standard postal shipping assist integration into clinical workflows and enable at-home collections from diverse populations, especially at-risk, minority populations without easy access to clinical services.

Citation Format: Savannah Colameco, Jean M. Macklaim, Ashlee Brown, Tara Crawford Parks. Room temperature stabilization of fecal samples supports important microbiome insights to expand access [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C024.