Endodontic and salivary isolates of Enterococcus faecalis integrate into biofilm from human salivary bacteria cultivated in vitro.
BACKGROUND
The aim of this study was to examine whether Enterococcus faecalis isolates from endodontic patients (from saliva and from a root canal) are able to prevail against salivary bacteria when grown in coculture in a biofilm reactor.


METHODS
Saliva that was tested to be free of E. faecalis was used as the inoculum. The fate of E. faecalis was examined by using culture techniques and fluorescence in situ hybridization (FISH).


RESULTS
The root canal isolate accounted for 37.4% of the biofilm and 31.9% of the planktonic phase when examined by the culture technique, whereas the proportions examined by FISH showed 15.3% in the biofilm and 11.7% in the planktonic phase. The saliva isolate (as examined by the culture technique) accounted for 32.4% in the biofilm and 27.1% in the planktonic phase, respectively, compared with 14.1% in the biofilm and 9.5% in the planktonic phase when examined by FISH analysis.


CONCLUSIONS
These results led to the suggestion that E. faecalis could persist in the biofilm of the human oral cavity. Because of the ubiquitous presence of E. faecalis, root canal infections may arise from different sources.
Al-Ahmad
Ali
A
Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University, Freiburg, Germany. ali.al-ahmad@uniklinikfreiburg.de
Müller
Nada
N
Wiedmann-Al-Ahmad
Margit
M
Sava
Irina
I
Hübner
Johannes
J
Follo
Marie
M
Schirrmeister
Jörg
J
Hellwig
Elmar
E
D000818:Animals; D000898:Antibiosis; D018441:Biofilms / Q000254:growth & development*; D002417:Cattle; D018920:Coculture Techniques; D015169:Colony Count, Microbial; D003743:Dental Enamel / Q000382:microbiology; D003773:Dental Plaque / Q000382:microbiology; D003786:Dental Pulp Cavity / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000502:physiology*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D018613:Microscopy, Confocal; D016133:Polymerase Chain Reaction / Q000379:methods; D012463:Saliva / Q000382:microbiology*; D037521:Virulence Factors / Q000032:analysis
D037521:Virulence Factors