Foodborne enterococci in oral biofilm: an invivo human study

Abstract number: P1907

Al-Ahmad A., Spitzmüller B., Maier J., Wittmer A., Follo M., Hellwig E., Jonas D.

Objectives: Persistence of microorganisms or reinfection are the main reasons for failure of root canal therapy. Enterococci, particularly Enterococcus faecalis, have frequently been isolated from root-filled teeth associated with periradicular lesions. Up to now enterococci are considered as transient and not belonging to the normal oral flora. The aim of this study was to examine the ability of food born enterococci to integrate in mature dental oral biofilm.

Methods: Six healthy volunteers with an age range of 25–26 wore dental splints loaded with equal sized pieces of BSE-free bovine enamel. After 3 days, the volunteers consumed cheese which included E. faecalis, Enterococcus faecium, Enterococcus avium and Enterococcus durans. The supragingival biofilm was analysed by culture technique. E. faecalis was also analysed using fluorescent in situ hybridisation (FISH). Isolated members of the different enterococci found in cheese and biofilm were also confirmed by 16S rRNA gene sequencing. All strains were characterised genotypically by macrorestriction analysis using the restriction endonuclease SmaI and pulsed-field gel electrophoresis. Molecular masses of all bacterial DNA fingerprints were determined using the control strain Staphylococcus aureus NCTC 8325. Similarities were presented as dendrograms.

Results:E. faecalis, E. faecium, E. avium and E. durans were isolated from the initial biofilm after 2 h, as well as from the mature dental plaque biofilm which developed after 5 days. Similarities between E. faecalis, E. faecium and E. avium isolated from cheese, as well as strains of these species isolated from the initial biofilm and from the 5 day-old biofilm, were revealed by macrorestriction analysis. E. faecium and E. avium integrated into an already existing 3 day-old biofilm. E. durans could be isolated from both the initial and 5 day-old oral biofilm, yet no similarities to the E. durans strains isolated from cheese were detected. E. faecalis was also detected in dental plaque biofilm using fluorescent in situ hybridisation (FISH). Individual differences among the tested volunteers were shown.

Conclusions:E. faecalis, E. avium and E. faecium could be resident in the dental oral biofilm and not only transient. Fermented food is one source of these enterococci in the oral cavity. The genotypic characterisation of enterococci strains is essential in order to study their origins within the oral cavity.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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