Molecular Analysis of Bacteria Associated with Apical Periodontitis and Their Suscebtability to Antimicrobial Peptides

Abstract

Periradicular diseases are among the most common inflammatory diseases that affect humans. Overwhelming evidence indicates that microorganisms infecting the root canal of the teeth are the major causative agents of these diseases. The main objective of the present investigation was to study the prevalence and relationship of F.Nucleatum, P.Gingivalis, T.Denticola, T. Forsythia and P.Endodontalis from different forms of apical periodontitis lesions, as well as to investigate the susceptibility of F.Nucleatum to a panel of antimicrobial peptides (AMPs). Method: Adult patients with one clinically and radiographically documented periapical lesion were included. Samples were collected by means of a size 15 Htype file and two sterile paper points from 80 cases of primary endodontic infections using aseptic technique. The prevalence and quantity of bacteria was determined using quantitative real time PCR. F. Nucleatum susceptibility to antimicrobial peptides LL37, α-Defensins-1, β- Defensin-1, β- Defensin -2 and β- Defensin -3 was assessed using ultra-sensitive radial diffusion assay. Results: F.nucleatum was found to be the most prevalent bacteria (60%) followed by T.denticola (46%), P.endodontalis (31%), P.gingivalis (24%) and T. forsythia (17%). A significant association was found between F,Nucleatum and T,denticola 5 with symptomatic apical periodontitis (p< 0.05)..F.Nucleatum showed susceptibility to LL-37,hBD-3,and hBD-2 with an MIC 10,16 and 40 μg/ml respectively. Conclusion P.gingivalis has the highest bacterial mean count among the other bacteria investigated. F.Nucleatum is the most prevalent bacteria among the bacteria under study. LL-37 displayed the highest antimicrobial activity against F.Nucleatum. Further studies testing the effect of antimicrobial peptides in microbial biofilm are needed.