(PR060) Analysis of the Interkingdom Microbiome Associated with Primary and Secondary/Persistent Endodontic Infection: A Cross-Sectional Study

Objective: To investigate the bacteriome and mycobiome in root canals of primary and secondary/persistent endodontic infections and explore the potential role of interkingdom interactions in endodontic infections.

Methods: Sixty-three patients were recruited from Temple Graduate Endodontic Clinic as follows: 30 patients with primary endodontic infection, 30 with secondary/persistent endodontic infection, and 3 patients undergoing elective extraction of sound teeth for orthodontic treatment (negative control). Samples were collected from the root canal and profiled for bacterial and fungal communities using 16S rRNA and ITS2 sequencing, respectively. Species-level taxonomy assignments were performed using a previously described Blastn-based algorithm. Downstream analysis of the data was performed with Phyloseq, Microbiome, Vegan and MaAsLin packages in R.

Results: Significant differences were observed in the bacteriome and mycobiome, in terms of alpha and beta-diversity as well as taxonomic profiles, between primary and secondary/persistent infections. Furthermore, novel interactions between fungal and bacterial communities were identified.

Conclusion: This study is the first to simultaneously characterize the fungal and bacterial communities in primary and secondary/persistent endodontic infections. The study uncovers novel bacterial-fungal interactions, providing new insights into the etiology of both types of endodontic infections.