Long-term stability at -80°C of oral wash and saliva samples for microbiome analyses
Slack et al.
The finding, in our words
Saliva samples collected using the OMNIgene ORAL device and oral wash samples remain stable for microbiome diversity and relative abundance analyses for up to five years when stored at -80°C. This supports the use of these self-collection methods for long-term prospective biobanking and decentralised clinical studies.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
Across 18 saliva samples, mouthwash collection gave higher alpha diversity than passive drooling on both Illumina and Nanopore platforms, and three preservation methods performed alike; mouthwash and simple collection are convenient decentralised options, provided a study keeps one collection method for all participants to avoid confounding.
A study found that fecal samples on FOBT cards and RNAlater, and oral samples in Scope mouthwash, remained stable for four days at room temperature, with fecal comparability ICCs ranging from 0.63 to 0.93. These methods support decentralised sampling, though consistent method choice is required as each may introduce modest differences.
This study compared four stool collection methods for infant gut microbiome analysis via post and found that the OMNIgene•GUT kit showed the closest agreement with the frozen standard compared to swabs or plain tubes. The findings suggest that stabilised collection offers a viable decentralised solution for parents to sample infant stool at home with minimal DNA degradation.
Oral rinse samples collected in Scope mouthwash remained stable at ambient temperature for four days, with high intraclass correlation for microbial diversity (Shannon index ICC 0.86), supporting their use in decentralised microbiome studies. However, comparability with OMNIgene ORAL samples was low, suggesting collection methods should not be mixed within a study.
The OMNIgene•GUT kit proved reliable for stool microsampling and ambient storage, with samples stored at room temperature for seven days showing comparable bacterial DNA quantity and diversity to fresh samples; transient phylum-level differences were seen at 24 hours but not at seven days. This supports decentralised, patient-centric microbiome research by enabling home self-collection and postal transport, while emphasising that DNA extraction method has greater impact on microbiome profiles than storage conditions.