Variation in bacterial DGGE patterns from human saliva: over time, between individuals and in corresponding dental...

Eubacterial 16S rDNA fingerprints of human saliva and dental plaque microcosm biofilms grown in the multi-plaque artificial mouth (MAM) were characterised using denaturing gradient gel electrophoresis (DGGE).

The stability of the bacterial community in the saliva of one individual collected over 7 years was assessed and compared with bacterial patterns in the saliva of 10 different individuals. DGGE was also used to assess changes in bacterial composition between saliva and mature plaque microcosms developed in the MAM from these 10 individual saliva samples.

A relatively stable bacterial community (>87% concordance) was maintained within the individual oral environment of the standard donor over 7 years of monitoring. By comparison, DGGE fingerprint patterns of saliva from 10 different donors displayed greater variability (66% concordance). Variability between individual DGGE profiles increased further in mature plaque microcosms grown from the saliva of the 10 donors (52% concordance) with an increase in detected species diversity and evidence for conserved similarity and hence the maintenance of organisation during community development.

These results suggest that stable ecological conditions were maintained long-term within the oral environment of the individual saliva donor but that transient fluctuations also occurred. The ecology and predominating microbiota in different individuals was host-specific and these differences were maintained to a degree during development into mature plaque microcosms. These findings also demonstrate the potential usefulness of applying DGGE to monitor temporal and developmental changes and possibly pathogenic patterns in oral bacterial communities from saliva and plaque.