Comparison of oral collection methods for 16S rRNA gene and shotgun metagenomic sequencing

We investigated how different sample collection methods affect oral microbiome studies by comparing unpreserved saliva, saliva preserved in glycerol, and mouthwash samples. We assessed their stability at room temperature and their intraindividual stability over six months. Samples were collected from 20 healthy participants at two time points six months apart; saliva samples were split, with half preserved in glycerol. Some samples were frozen immediately, while others were stored at room temperature for a week. DNA was extracted using PowerSoil Pro, followed by 16S rRNA gene and shotgun metagenomic sequencing. Intraclass correlation coefficients (ICCs) from taxonomic and functional tables were used to assess variability, and sample size requirements were calculated based on... (for more see dbGaP study page.)