The Influence of Stationary and exponential Growth Phase of Probiotic Lactobacilli Towards Aggregatibacter actinomycetemcomitans Biofilm

Background: Bacterial biofilm of the oral cavity contributes to the dispersion of pathogenic organisms to other organs, particularly in immunocompromised patients. Lactobacilli own potent activity against the biofilm of the periodontal pathogen. The study aims to evaluate the inhibition activity of the probiotics lactobacilli’s cells and supernatant during exponential and stationary phases against Aggregatibacter actinomycetemcomitans’s biofilm exponential phase.Methods: Five Lactobacillus sp. and four A. actinomycetemcomitans strains were used during preliminary studies. Then, two chosen species of Lactobacillus sp. were used to determine inhibition activity towards A. actinomycetemcomitans’s biofilm using biofilm inhibition assay of a 96-well plate. Data of three replicates were presented as mean ± SD (standard deviation). The comparison was performed using Student t-test Software with P-value < 0.05 as the significant level.Results: A significant difference in biofilm formation was observed in all four A. actinomycetemcomitans strains compared to the co-cultures biofilm assay with all probiotic lactobacilli for both cells and supernatant.  All probiotic lactobacilli show biofilm inhibition activity. Interestingly, a significant difference (p < 0.05) was observed between the stationary and exponential phases in the inhibitory activity of L. casei NBRC 15883’s cells. Whereas no significant difference was found for the biofilm inhibition activity of L. casei NBRC 15883’s supernatant. Otherwise, there was no significant difference (p > 0.05) in inhibition activity between the exponential and stationary phase of L. johnsonii NBRC 13952 in both cells and supernatant.Conclusion: This finding suggests a dynamic effect of the probiotic Lactobacillus sp. as part of counteraction strategies against the periodontal pathogen biofilm. The differential effect of stationary and exponential phases might indicate different mechanisms or compounds that require further study.Keywords: Aggregatibacter actinomycetemcomitans; Periodontal disease; Biofilm formation; Probiotic lactobacilli; Biofilm inhibition