Fig. 1.

Diversity analyses of the bacteriome of root canal infections. a Observed species richness (number of OTUs/sample). b Shannon diversity index of within-sample diversity. c Bray-Curtis similarity index of between-sample diversity. For analysis of the species richness and Shannon diversity index, Wilcoxon signed-rank test compared apical (N = 22) to coronal root segments (N = 22; light gray) and the Mann-Whitney U test compared fungi positive (N = 21) to fungi negative root segments (N = 24; dark gray). For analysis of the Bray-Curtis similarity index, the Kruskal-Wallis test compared the paired root samples to the apical and coronal root segments as well as to the fungi-positive and fungi-negative root segments, with post hoc analysis using the Mann-Whitney U test and an FDR correction (q* = 0.033). *p < 0.001