Effects of the long-term storage of human fecal microbiota samples collected in RNAlater

Sci Rep. 2019 Jan 24;9(1):601. doi: 10.1038/s41598-018-36953-5.

Abstract

The adequate storage of fecal samples from clinical trials is crucial if analyses are to be performed later and in long-term studies. However, it is unknown whether the composition of the microbiota is preserved during long-term stool storage (>1 year). We therefore evaluated the influence of long-term storage on the microbiota composition of human stool samples collected in RNAlater and stored for approximately five years at -80 °C. We compared storage effects on stool samples from 24 subjects with the effects of technical variation due to different sequencing runs and biological variation (intra- and inter-subject), in another 101 subjects, based on alpha-diversity, beta-diversity and taxonomic composition. We also evaluated the impact of initial alpha-diversity and fecal microbiota composition on beta-diversity instability upon storage. Overall, long-term stool storage at -80 °C had only limited effects on the microbiota composition of human feces. The magnitude of changes in alpha- and beta- diversity and taxonomic composition after long-term storage was similar to inter-sequencing variation and smaller than biological variation (both intra- and inter-subject). The likelihood of fecal samples being affected by long-term storage correlated with the initial relative abundance of some genera and tend to be affected by initial taxonomic richness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria / genetics
  • Bacteria / isolation & purification
  • Biodiversity
  • Feces / microbiology*
  • Humans
  • Microbiota*
  • Preservation, Biological / methods*
  • RNA, Ribosomal, 16S / chemistry
  • RNA, Ribosomal, 16S / metabolism
  • Specimen Handling
  • Temperature

Substances

  • RNA, Ribosomal, 16S