Abstract

ABSTRACT: Molecular techniques that provide valuable information about the epidemiology of oral strains. The purpose of this study was to determine the genetic relatedness of 83 Enterococcus faecalis strains isolated from treated root canals. These strains were obtained from patients who were treated for persistent endodontic infections. E. faecalis isolates were molecular typed by Pulsed Field Gel Electrophoresis using SmaI. Ten clonal groups and 13 pulse types with 38.7 % similarity for the less related strains were identified. Genetic heterogeneity among strains from different patients and a high level of genetic homogeneity among intrapatient strains were observed. Therefore, restriction endonuclease fingerprinting of genomic DNA from E. faecalis strains confirmed the polyclonality of the isolates obtained from the root canals of patients diagnosed with persistent endodontic infections, compared with other reports. These results provide additional data for a better understanding of the epidemiological aspects of root canal infections by E. faecalis.