Geographical Variation in Primary Endodontic Infections

Objectives: The aim of this study was to evaluate the root canal microbiome in primary endodontic infections from two geographical populations.
Methods: This is a secondary bioinformatic analysis of sequencing data obtained from primary endodontic infections from Sweden (N=24) and USA (N=21), (PMID 33260621, 36334085). Taxa were classified using SILVA v.138. Differences among the 10 most abundant genera were evaluated using Kruskal–Wallis test. Alpha diversity indices were calculated in mothur. The Shannon and Chao1 indices were used. Analyses of similarity (ANOSIM) to determine differences in community composition were used with Bonferroni correction for multiple comparisons.
Results: A similar number of OTUs and alpha-diversity values (Shannon and Chao1 indices) were observed from samples obtained in USA and Sweden
P > 0.05. Ten microbial genera comprised the predominant taxa ≥ 2.8% and included Fusobacterium, Prevotella, Eubacterium, Parvimonas, Mogibacterium, Lancefieldella, Porphyromonas, Dialister, Streptococcus and Veillonella. Despite the lack of differences in abundance among the most relevant genera, Kruskal-Wallis ≥ 0.063, geography showed significant effects on community composition via an ANOSIM using Bray Curtis dissimilarities, R: 0.13, P: 0.001.
Conclusions: Multiple similarities were found between the two geographical locations including similar number of operational taxonomic units, alpha diversity values and genus-level composition. Significant differences were found in beta diversity community composition.