Person-specific microbiota responses to sucrose of the plaque microcosm development

That there are between-individual differences in the oral microbiota is well-established. This implies person-specific differences in reaction to the major driver of cariogenic plaque formation; their microbiota response to sucrose exposure. Objective: Using checkerboard analysis, evaluate individual-specific differences in the ecological response of the oral microbiota sucrose during the development in vitro of dental plaque microcosm biofilms developed from 24 people in the Multiplaque Artificial Mouth. Methods: Plaque microcosm biofilms were cultured for 11 days, separately from plaque-enriched saliva from 24 people. The effects of growth exposed to 3x/day 10% sucrose 6min pulses was compared with growth in artificial saliva (DMM) only. The plaque microbiota was characterized by Checkerboard DNA:DNA hybridization and analysed using community ordination cluster analysis and PCA of the ratio of each species in plaques exposed to sucrose to those not sucrose exposed. Results: Cluster analysis separated sucrose-pulsed from non-pulsed plaques. PCA analysis of sucrose responsiveness separated people into three groups and a more dissimilar set of individuals. Most species varied considerably within each group, although the mean levels for each cluster were generally similar, including the putative caries pathogens Streptococcus mutans and Leptotrichia buccalis. A large positive response to sucrose that differed among PCA groups was seen for Actinomyces naeslundii, Actinomyces israelii, and for targets of the Candida albicans probe. Veillonella parvula also varied among groups but surprisingly was mostly suppressed by sucrose exposure. In contrast to these results in these highly biodiverse microcosm plaques, growth of both V. parvula and S. mutans in mono-culture are generally increased by sucrose exposure. This discrepancy reinforces the difficulty of extrapolating the behaviour of species in a mono-culture to that in the plaque environment. Conclusion: In different people, the oral microbiota response to sucrose exposure differs and therefore they also differ in caries pathophysiology. Funded HRC(NZ).