University Archives

Background: Several Lactobacillus-based probiotic formulations have been developed to restore a
healthy microbiota to the oral cavity and prevent periodontal disease and/or caries. The ability of
Lactobacilli to produce acidic environments and in some cases antimicrobial compounds, make them
encouraging candidates to reduce the levels of periodontal pathogens such a P. gingivalis.
Objective: This study evaluated the ability of three different Lactobacillus-based probiotics to
interfere with P. gingivalis (Pg) biofilm formation: Biogaia® (L. reuteri), Vigiis® (L. paracasei), and
StellaLife® (a collection of 8 lactobacillus probiotic strains, and Streptococcus salivarius).
Methods: Biofilms were established in artificial saliva + 0.5% sucrose and 1.4mg/ml peptone.
Overnight cultures (anaerobic for Pg) were washed and resuspended in bacterial growth media at
OD600=1.0. Equal volumes of Pg or probiotic were added with either Pg added to wells of a 24-well
plate (1ml total) 3 hours before the probiotic, the probiotic added 3 hours ahead of Pg, or strains
were added simultaneously. Crystal violet staining was used to measure biofilm thickness and pH of
the resulting wells after 24 hours was measured. The % of the biofilm present composed of Pg was
determined by quantitative PCR on wells colonized with Pg alone (100% Pg) or Pg competing with
probiotics.
Results: While in many cases addition of a Lactobacillus-based probiotic does not decrease overall
biomass based on crystal violet staining, DNA analysis shows that addition of either Biogaia® (L.
reuteri) or the Stella Life® formulation prior to Pg led to 75% or >90% decrease in the level of Pg in
the total biofilm microbiota, respectively. Even simultaneous addition of Pg and StellaLife® led to
>95% decrease in Pg levels in the mixed biofilm. Vigiis® (L. paracasei) showed a more modest effect
on the level of Pg in biofilms. pH levels dropped in the absence of Pg, owing to acid production by
lactobacilli.
Conclusions: The probiotic StellaLife® can drastically reduce Pg levels in biofilms whether added
simultaneously or when added before of Pg. Biogaia® can reduce Pg levels in biofilms when added
prior to Pg.