Comparison of fecal and oral collection methods for studies of the human microbiota in two Iranian cohortsOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study examined how fecal and oral sample collection methods, along with room temperature storage, affect measurements of the human microbiota. Researchers compared fecal preservation using RNAlater and fecal occult blood test (FOBT) cards over four days at room temperature. They also compared oral sampling using OMNIgene ORAL kits versus Scope mouthwash. Comparability and stability were assessed using interclass correlation coefficients (ICCs) across alpha and beta diversity metrics and phylum-level relative abundance.
Who was studied?
Participants were drawn from two Iranian cohorts: a rural population in Yazd (n = 46) and an urban population in Gonbad (n = 38). Both fecal and oral samples were collected from these participants for the method-comparison analyses. The abstract does not provide further demographic detail such as age or sex distribution.
What were the most important findings?
Fecal samples remained stable at room temperature for four days, with generally high ICCs across microbial metrics for both RNAlater and FOBT cards. Comparability between RNAlater and FOBT cards was also high, with ICCs ranging from 0.63 for relative abundance of Firmicutes to 0.93 for unweighted UniFrac. Scope mouthwash likewise showed generally high ICCs for stability. The abstract does not mention Desulfovibrio, sulfate-reducing bacteria, hydrogen sulfide, or sulfur metabolism, so this study is summarized on its own terms.
What are the greatest implications of this study?
The findings support the feasibility of using RNAlater, FOBT cards, and Scope mouthwash for microbiota collection in field settings where cold storage may not be available for several days. This has practical value for prospective cohort studies conducted in resource-limited or geographically dispersed settings, including the rural and urban Iranian sites studied here. Reliable room temperature stability could reduce logistical burden and cost for large-scale microbiome research.