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Enterococcus faecalis infection in root canals - host-derived or exogenous source?

R Vidana1, A Sullivan, H Billström

  • 1Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.

Letters in Applied Microbiology
|December 16, 2010
PubMed
Abstract

Insights

Refractory endodontic infections involving Enterococcus faecalis (Ent. faecalis) are likely not from the patient's own microflora. This study suggests these persistent infections originate from external sources, not the gut or oral microbiome.

Area of Science:

  • Microbiology
  • Endodontics
  • Infectious Diseases

Background:

  • Enterococcus faecalis (Ent. faecalis) is frequently found in persistent endodontic infections.
  • The prevalence of Ent. faecalis in failed root canal treatments ranges from 24% to 77%.
  • The origin of Ent. faecalis in endodontic infections is unclear as it's not a typical oral bacterium.

Purpose of the Study:

  • To investigate the origin of Enterococcus faecalis in refractory endodontic infections.
  • To determine if Ent. faecalis in root canals is of endogenous (from the patient's own flora) or exogenous (external) origin.

Main Methods:

  • Fifty patients with apical periodontitis requiring endodontic retreatment were enrolled.
  • Samples were collected from root canals, saliva, and feces for microbiological analysis.
  • Pulsed-field gel electrophoresis (PFGE) was used to genetically compare Ent. faecalis isolates.

Main Results:

  • Enterococci were detected in root canal samples from 16% (8/50) of patients.
  • Genetic analysis revealed no relationship between root canal Ent. faecalis and isolates from fecal samples (gastrointestinal microflora).
  • Enterococci were not found in the saliva samples of these patients.

Conclusions:

  • Endodontic infections with Enterococcus faecalis are likely not derived from the patient's endogenous microflora.
  • The findings strongly suggest that Ent. faecalis in these refractory endodontic infections is of exogenous origin.
  • This study provides the first genetic comparison of endodontic Ent. faecalis with isolates from the host's normal microflora.

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