(PR42) Bacterial Chemotaxis Genes and Apical Periodontitis. A Whole-Metagenome Shotgun Based Study.

Chemotaxis is a process by which bacteria sense chemical gradients in their environment and then move towards more favorable conditions. Despite the pathogenic potential of the root canal microbiome, the abundance of genes encoding bacterial chemotaxis genes is unknown. This study aimed to identify genes encoding the bacterial chemotaxis pathway in cases of primary and secondary/persistent apical periodontitis using whole genome shotgun sequencing. 37 samples from patients with primary and secondary root canal infections were evaluated using whole genome shotgun sequencing. The genes encoding the bacterial chemotaxis pathway and their respective bacterial species were identified. Libraries were made using ¼ Nextera XT reactions and sequencing was done on the Novaseq with a target of 15M-20M reads per sample. Taxonomic and functional annotations were made using Kegg, MetaPhIAn3, and HUMAnN3 after removal of host sequences’ DNA using knead data with normalization to copies per million. The U-Mann Whitney test was used to compare differences between primary and secondary infections. There was a significant difference in the number of genes encoding the bacterial chemotaxis pathway between primary and secondary/persistent apical periodontitis (P =0.0018). This pathway was overrepresented in primary endodontic infections. The most prevalent bacteria encoding the studied pathway in primary endodontics infections were F. nucleatum, O.uli, P. propionicum, and S. sputigena.The most prevalent species in secondary infections were P. propionicum and O. uli. Multiple bacterial genes associated with bacterial chemotaxis were found in endodontic infections. The most prevalent bacteria associated with the studied pathway were F. nucleatum, O. uli, P. propionicum, and S. sputigena.