Deep Sequencing Analyses of Low Density Microbial Communities: Working at the Boundary of Accurate Microbiota Detection
Figure 2
Average relative abundance of the 6 main taxa in undiluted saliva and dilutions 1 to 3 (107 to 105 bacteria per ml, respectively).
Shown in error bars is the standard deviation per dilution indicative of the variation between DNA extraction methods. We used ANOVA statistics to test for significant differences. Dilution 3 shows a significant increase in Proteobacteria (p<0.001, mean 26,11% and 3.6%, SD 17.5 and 2.5% respectively) and a significant decrease in Bacteroidetes (p<0.001, mean 18.99% and 43.1% respectively) compared to the undiluted saliva samples. By diluting the sample up to 105 bacteria per ml an increase in Firmicutes, mostly Veilonella, was observed, and a decrease in Bacteroidetes, mostly Prevotella.