Individual microflora beget unique oral microcosms

Aims: To examine the efficacy of the multiple Sorbarod device (MSD) for the reproduction of inter-individual variations in oral microbiotas. The MSD supports sessile growth on parallel cellulose filters, perfused with artificial saliva. This enables biofilms (BF) to be grown and sampled, together with released cells in eluted medium (perfusates, PAs). Methods and Results: Two sets of triplicate MSDs were established One set. was inoculated using fresh saliva from three separate volunteers; the second set was inoculated from one saliva donor. Both were incubated in an anaerobic cabinet. BF and PA were analysed at 24-h intervals by PCR-denaturing gradient gel electrophoresis (DGGE) of 16S rDNA. Hierarchical dendrograms were constructed in order to sort community fingerprints over time, based on community relatedness. The MSD supported complex oral communities, as evidenced by DGGE (> 20 distinct DGGE bands) and confocal scanning laser microscopy. DGGE band sequencing revealed bacteriological diversity and a high incidence of anaerobic species, including Prevotella sp. Dendrograms demonstrated marked inter-individual variation in the relative species abundance within salivary inocula from different volunteers (DV) and each associated MSD (all > 45%, majority c. 85% concordance). Less variation was shown between triplicate models established using saliva from a single volunteer (SV) (all > 58%; majority c. 95% concordance). PAs clustered together with the associated biofilms and inocula in the majority of cases for the DV MSDs whilst SV MSD community profiles clustered between replicate MSDs. Conclusions: Data indicate that marked inter-individual variations in human salivary composition can be partially replicated in individualized MSD microcosms. Significance and Impact of the Study: This study demonstrates the in vitro reproduction of individual oral microbiotas and suggests that taking inter-individual variability into account will increase the relevance of microcosm studies.