Limosilactobacillus reuteri-Fusobacterium nucleatum Interactions Modulate Biofilm Composition and Immunogenicity

Area of Science:

• Oral microbiology
• Probiotics
• Biofilm formation

Background:

• Interactions between Limosilactobacillus reuteri and oral bacteria are not well understood.
• Fusobacterium nucleatum plays a key role in oral biofilm development.
• L. reuteri is a known probiotic with potential oral health benefits.

Purpose of the Study:

• To characterize the coaggregation between L. reuteri and F. nucleatum.
• To determine the impact of this interaction on biofilm composition.
• To assess the effect on the immunogenicity of oral bacterial aggregates.

Main Methods:

• In vitro experiments using L. reuteri strains (DSM 17938, ATCC PTA 5289) and oral bacteria (F. nucleatum ATCC 25586, P. gingivalis W50).
• Tube coaggregation assay and confocal microscopy to evaluate strain interactions.
• Biofilm composition analysis via microscopy and culture.
• Immunogenicity assessment using human cell lines (fibroblasts, epithelial cells, monocytes).

Main Results:

• Both L. reuteri strains coaggregated with F. nucleatum, reducing F. nucleatum in biofilms by 1000-fold.
• Coaggregation significantly lowered the immunogenicity of F. nucleatum.
• L. reuteri coaggregation also led to a 50% reduction in P. gingivalis within the biofilm.

Conclusions:

• L. reuteri exhibits novel probiotic mechanisms through coaggregation with F. nucleatum.
• This interaction modulates F. nucleatum's immunogenicity and its role as a bridging species.
• Altered biofilm composition by L. reuteri coaggregation limits oral dysbiosis.