16S and SCFA analysis of human stool samples comparing different collection/preservation buffers stored at different temperatures.

Preserving stool sample integrity, in terms of microbial community composition and metabolic function is crucial to confidently define the role of the gut microbiota in health and disease. This presents a challenge for any human studies which rely on participants self-collecting and returning stool samples as this introduces variability and uncertainty of sample storage/handling. Here we tested 3 stool sample collection/preservation buffers stored at different temperatures (room temperature (20oC), 4oC and -80oC) for up to 3 days and quantified differences in observed microbial community composition and metabolic function compared against immediately snap-frozen stool. We found that the choice of preservation buffer had the largest effect on the resulting microbial and metabolomic profiles, with storage temperature and time of storage also contributing to profile changes. To our knowledge we present the first study to consider both microbial composition and functional profiles when defining the optimum stool sample collection strategy which is participant friendly as well as being scientifically robust.